21 Flying Images 2.0 crack serial keygen

21 Flying Images 2.0 crack serial keygen

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21 Flying Images 2.0 crack serial keygen - sorry, that

Trusted platform module security defeated in 30 minutes, no soldering required

Trusted platform module security defeated in 30 minutes, no soldering required
with 104 posters participating, including story author

Let’s say you’re a large company that has just shipped an employee a brand-new replacement laptop. And let’s say it comes preconfigured to use all the latest, best security practices, including full-disk encryption using a trusted platform module, password-protected BIOS settings, UEFI SecureBoot, and virtually all other recommendations from the National Security Agency and NIST for locking down federal computer systems. And let’s say an attacker manages to intercept the machine. Can the attacker use it to hack your network?

Research published last week shows that the answer is a resounding "yes." Not only that, but a hacker who has done her homework needs a surprisingly short stretch of time alone with the machine to carry out the attack. With that, the hacker can gain the ability to write not only to the stolen laptop but to the fortified network it was configured to connect to.

Researchers at the security consultancy Dolos Group, hired to test the security of one client’s network, received a new Lenovo computer preconfigured to use the standard security stack for the organization. They received no test credentials, configuration details, or other information about the machine. An analysis of the BIOS settings, boot operation, and hardware quickly revealed that the security measures in place were going to preclude the usual hacks, including:

Fort Knox and the not-so-armored car

With little else to go on, the researchers focused on the trusted platform module, or TPM, a heavily fortified chip installed on the motherboard that communicates directly with other hardware installed on the machine. The researchers noticed that, as is the default for disk encryption using Microsoft’s BitLocker, the laptop booted directly to the Windows screen, with no prompt for entering a PIN or password. That meant the TPM was where the sole cryptographic secret for unlocking the drive was stored.

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Microsoft recommends overriding the default and using a PIN or password only for threat models that anticipate an attacker with enough skill and time alone with an unattended target machine to open the case and solder motherboard devices. After completing their analysis, the researchers said that the Microsoft advice is inadequate because it opens devices to attacks that can be performed by abusive spouses, malicious insiders, or other people who have fleeting private access.

“A pre-equipped attacker can perform this entire attack chain in less than 30 minutes with no soldering, simple and relatively cheap hardware, and publicly available tools,” the Dolos Group researchers wrote in a post, “a process that places it squarely into Evil-Maid territory.”

TPMs have multiple layers of defenses that prevent attackers from extracting or tampering with the data they store. For instance, an analysis more than 10 years ago by reverse-engineer Christopher revealed that a TPM chip made by Infineon was designed to self-destruct if it was physically penetrated. Optical sensors, for instance, detected ambient light from luminous sources. And a wire mesh that covered the microcontroller was aimed at disabling the chip should any of its electrical circuits be disturbed.

With little hope of cracking the chip inside the Lenovo laptop, the Dolos researchers sought other ways they might be able to extract the key that decrypted the hard drive. They noticed that the TPM communicated with the CPU using serial peripheral interface, a communications protocol for embedded systems.

Abbreviated as SPI, the firmware provides no encryption capabilities of its own, so any encryption must be handled by the devices the TPM is communicating with. Microsoft’s BitLocker, meanwhile, doesn’t use any of the encrypted communications features of the latest TPM standard. If the researchers could tap into the connection between the TPM and the CPU, they might be able to extract the key.

They wrote:

Getting around the TPM in this manner is akin to ignoring Fort Knox and focusing on the not-so-armored car coming out of it.

In order to sniff the data moving over the SPI bus, we must attach leads or probes to the pins (labeled above as MOSI, MISO, CS, and CLK) on the TPM. Normally that is simple but there is a practical problem in this case. This TPM is on a VQFN32 footprint, which is very tiny. The “pins” are actually only 0.25mm wide and spaced 0.5mm apart. And those “pins” aren’t actually pins, they are flat against the wall of the chip so it’s physically impossible to attach any sort of clip. You could solder “fly leads” to the solder pads but that’s a hassle and tends to be a very physically unstable connection. Alternatively a common tactic is to locate in-series resistors to solder to, but they were just as small, and even more fragile. This was not going to be easy.

But before we got started we figured there might be another way. Many times SPI chips share the same “bus” with other SPI chips. It’s a technique hardware designers use to make connections simpler, save on cost, and make troubleshooting/programming easier. We started looking throughout the board for any other chip that might be on the same bus as the TPM. Maybe their pins would be larger and easier to use. After some probing and consulting the schematics, it turned out that the TPM shared a SPI bus with a single other chip, the CMOS chip, which definitely had larger pins. In fact, the CMOS chip had just about the largest pin size you can find on standard motherboards, it was a SOP-8 (aka SOIC-8).

Short for complementary metal–oxide–semiconductor, a CMOS chip on a PC stores the BIOS settings, including the system time and date and hardware settings. The researchers connected a Saleae logic analyzer to the CMOS. In short order, they were able to extract every byte moving through the chip. The researchers then used the bitlocker-spi-toolkit written by Henri Numi to isolate the key inside the mass of data.

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With the hard drive decrypted, the researchers combed through the data in search of something—encrypted or plaintext passwords, maybe exposed sensitive files or similar things—that might bring them closer to their goal of accessing the client’s network. They soon hit upon something: Palo Alto Networks’ Global Protect VPN client that had come pre-installed and preconfigured.

One feature of the VPN is that it can establish a VPN connection before a user logs in. The capability is designed to authenticate an endpoint and enable domain scripts to run as soon as the machine powers on. This is useful because it allows admins to manage large fleets of machines without knowing the password for each one.

Источник: [https://torrent-igruha.org/3551-portal.html]

An Overview of Cryptography

1. INTRODUCTION

Does increased security provide comfort to paranoid people? Or does security provide some very basic protections that we are naive to believe that we don't need? During this time when the Internet provides essential communication between literally billions of people and is used as a tool for commerce, social interaction, and the exchange of an increasing amount of personal information, security has become a tremendously important issue for every user to deal with.

There are many aspects to security and many applications, ranging from secure commerce and payments to private communications and protecting health care information. One essential aspect for secure communications is that of cryptography. But it is important to note that while cryptography is necessary for secure communications, it is not by itself sufficient. The reader is advised, then, that the topics covered here only describe the first of many steps necessary for better security in any number of situations.

This paper has two major purposes. The first is to define some of the terms and concepts behind basic cryptographic methods, and to offer a way to compare the myriad cryptographic schemes in use today. The second is to provide some real examples of cryptography in use today. (See Section A.4 for some additional commentary on this...)

DISCLAIMER: Several companies, products, and services are mentioned in this tutorial. Such mention is for example purposes only and, unless explicitly stated otherwise, should not be taken as a recommendation or endorsement by the author.

2. BASIC CONCEPTS OF CRYPTOGRAPHY

Cryptography — the science of secret writing — is an ancient art; the first documented use of cryptography in writing dates back to circa 1900 B.C. when an Egyptian scribe used non-standard hieroglyphs in an inscription. Some experts argue that cryptography appeared spontaneously sometime after writing was invented, with applications ranging from diplomatic missives to war-time battle plans. It is no surprise, then, that new forms of cryptography came soon after the widespread development of computer communications. In data and telecommunications, cryptography is necessary when communicating over any untrusted medium, which includes just about any network, particularly the Internet.

There are five primary functions of cryptography:

  1. Privacy/confidentiality: Ensuring that no one can read the message except the intended receiver.
  2. Authentication: The process of proving one's identity.
  3. Integrity: Assuring the receiver that the received message has not been altered in any way from the original.
  4. Non-repudiation: A mechanism to prove that the sender really sent this message.
  5. Key exchange: The method by which crypto keys are shared between sender and receiver.

In cryptography, we start with the unencrypted data, referred to as plaintext. Plaintext is encrypted into ciphertext, which will in turn (usually) be decrypted back into usable plaintext. The encryption and decryption is based upon the type of cryptography scheme being employed and some form of key. For those who like formulas, this process is sometimes written as:

C = Ek(P)
P = Dk(C)

      where P = plaintext, C = ciphertext, E = the encryption method, D = the decryption method, and k = the key.

Given this, there are other functions that might be supported by crypto and other terms that one might hear:

  • Forward Secrecy (aka Perfect Forward Secrecy): This feature protects past encrypted sessions from compromise even if the server holding the messages is compromised. This is accomplished by creating a different key for every session so that compromise of a single key does not threaten the entirely of the communications.
  • Perfect Security: A system that is unbreakable and where the ciphertext conveys no information about the plaintext or the key. To achieve perfect security, the key has to be at least as long as the plaintext, making analysis and even brute-force attacks impossible. One-time pads are an example of such a system.
  • Deniable Authentication (aka Message Repudiation): A method whereby participants in an exchange of messages can be assured in the authenticity of the messages but in such a way that senders can later plausibly deny their participation to a third-party.

In many of the descriptions below, two communicating parties will be referred to as Alice and Bob; this is the common nomenclature in the crypto field and literature to make it easier to identify the communicating parties. If there is a third and fourth party to the communication, they will be referred to as Carol and Dave, respectively. A malicious party is referred to as Mallory, an eavesdropper as Eve, and a trusted third party as Trent.

Finally, cryptography is most closely associated with the development and creation of the mathematical algorithms used to encrypt and decrypt messages, whereas cryptanalysis is the science of analyzing and breaking encryption schemes. Cryptology is the umbrella term referring to the broad study of secret writing, and encompasses both cryptography and cryptanalysis.

3. TYPES OF CRYPTOGRAPHIC ALGORITHMS

There are several ways of classifying cryptographic algorithms. For purposes of this paper, they will be categorized based on the number of keys that are employed for encryption and decryption, and further defined by their application and use. The three types of algorithms that will be discussed are (Figure 1):

  • Secret Key Cryptography (SKC): Uses a single key for both encryption and decryption; also called symmetric encryption. Primarily used for privacy and confidentiality.
  • Public Key Cryptography (PKC): Uses one key for encryption and another for decryption; also called asymmetric encryption. Primarily used for authentication, non-repudiation, and key exchange.
  • Hash Functions: Uses a mathematical transformation to irreversibly "encrypt" information, providing a digital fingerprint. Primarily used for message integrity.

FIGURE 1: Three types of cryptography: secret key, public key, and hash function.

3.1. Secret Key Cryptography

Secret key cryptography methods employ a single key for both encryption and decryption. As shown in Figure 1A, the sender uses the key to encrypt the plaintext and sends the ciphertext to the receiver. The receiver applies the same key to decrypt the message and recover the plaintext. Because a single key is used for both functions, secret key cryptography is also called symmetric encryption.

With this form of cryptography, it is obvious that the key must be known to both the sender and the receiver; that, in fact, is the secret. The biggest difficulty with this approach, of course, is the distribution of the key (more on that later in the discussion of public key cryptography).

Secret key cryptography schemes are generally categorized as being either stream ciphers or block ciphers.

A) Self-synchronizing stream cipher. (From Schneier, 1996, Figure 9.8)

B) Synchronous stream cipher. (From Schneier, 1996, Figure 9.6)

FIGURE 2: Types of stream ciphers.

Stream ciphers operate on a single bit (byte or computer word) at a time and implement some form of feedback mechanism so that the key is constantly changing. Stream ciphers come in several flavors but two are worth mentioning here (Figure 2). Self-synchronizing stream ciphers calculate each bit in the keystream as a function of the previous n bits in the keystream. It is termed "self-synchronizing" because the decryption process can stay synchronized with the encryption process merely by knowing how far into the n-bit keystream it is. One problem is error propagation; a garbled bit in transmission will result in n garbled bits at the receiving side. Synchronous stream ciphers generate the keystream in a fashion independent of the message stream but by using the same keystream generation function at sender and receiver. While stream ciphers do not propagate transmission errors, they are, by their nature, periodic so that the keystream will eventually repeat.

FIGURE 3: Feistel cipher. (Source: Wikimedia Commons)

A block cipher is so-called because the scheme encrypts one fixed-size block of data at a time. In a block cipher, a given plaintext block will always encrypt to the same ciphertext when using the same key (i.e., it is deterministic) whereas the same plaintext will encrypt to different ciphertext in a stream cipher. The most common construct for block encryption algorithms is the Feistel cipher, named for cryptographer Horst Feistel (IBM). As shown in Figure 3, a Feistel cipher combines elements of substitution, permutation (transposition), and key expansion; these features create a large amount of "confusion and diffusion" (per Claude Shannon) in the cipher. One advantage of the Feistel design is that the encryption and decryption stages are similar, sometimes identical, requiring only a reversal of the key operation, thus dramatically reducing the size of the code or circuitry necessary to implement the cipher in software or hardware, respectively. One of Feistel's early papers describing this operation is "Cryptography and Computer Privacy" (Scientific American, May 1973, 228(5), 15-23).

Block ciphers can operate in one of several modes; the following are the most important:

  • Electronic Codebook (ECB) mode is the simplest, most obvious application: the secret key is used to encrypt the plaintext block to form a ciphertext block. Two identical plaintext blocks, then, will always generate the same ciphertext block. ECB is susceptible to a variety of brute-force attacks (because of the fact that the same plaintext block will always encrypt to the same ciphertext), as well as deletion and insertion attacks. In addition, a single bit error in the transmission of the ciphertext results in an error in the entire block of decrypted plaintext.
  • Cipher Block Chaining (CBC) mode adds a feedback mechanism to the encryption scheme; the plaintext is exclusively-ORed (XORed) with the previous ciphertext block prior to encryption so that two identical plaintext blocks will encrypt differently. While CBC protects against many brute-force, deletion, and insertion attacks, a single bit error in the ciphertext yields an entire block error in the decrypted plaintext block and a bit error in the next decrypted plaintext block.
  • Cipher Feedback (CFB) mode is a block cipher implementation as a self-synchronizing stream cipher. CFB mode allows data to be encrypted in units smaller than the block size, which might be useful in some applications such as encrypting interactive terminal input. If we were using one-byte CFB mode, for example, each incoming character is placed into a shift register the same size as the block, encrypted, and the block transmitted. At the receiving side, the ciphertext is decrypted and the extra bits in the block (i.e., everything above and beyond the one byte) are discarded. CFB mode generates a keystream based upon the previous ciphertext (the initial key comes from an Initialization Vector [IV]). In this mode, a single bit error in the ciphertext affects both this block and the following one.
  • Output Feedback (OFB) mode is a block cipher implementation conceptually similar to a synchronous stream cipher. OFB prevents the same plaintext block from generating the same ciphertext block by using an internal feedback mechanism that generates the keystream independently of both the plaintext and ciphertext bitstreams. In OFB, a single bit error in ciphertext yields a single bit error in the decrypted plaintext.
  • Counter (CTR) mode is a relatively modern addition to block ciphers. Like CFB and OFB, CTR mode operates on the blocks as in a stream cipher; like ECB, CTR mode operates on the blocks independently. Unlike ECB, however, CTR uses different key inputs to different blocks so that two identical blocks of plaintext will not result in the same ciphertext. Finally, each block of ciphertext has specific location within the encrypted message. CTR mode, then, allows blocks to be processed in parallel — thus offering performance advantages when parallel processing and multiple processors are available — but is not susceptible to ECB's brute-force, deletion, and insertion attacks.

A good overview of these different modes can be found at CRYPTO-IT.

Secret key cryptography algorithms in use today — or, at least, important today even if not in use — include:

  • Data Encryption Standard (DES): One of the most well-known and well-studied SKC schemes, DES was designed by IBM in the 1970s and adopted by the National Bureau of Standards (NBS) [now the National Institute of Standards and Technology (NIST)] in 1977 for commercial and unclassified government applications. DES is a Feistel block-cipher employing a 56-bit key that operates on 64-bit blocks. DES has a complex set of rules and transformations that were designed specifically to yield fast hardware implementations and slow software implementations, although this latter point is not significant today since the speed of computer processors is several orders of magnitude faster today than even twenty years ago. DES was based somewhat on an earlier cipher from Feistel called Lucifer which, some sources report, had a 112-bit key. This was rejected, partially in order to fit the algorithm onto a single chip and partially because of the National Security Agency (NSA). The NSA also proposed a number of tweaks to DES that many thought were introduced in order to weaken the cipher; analysis in the 1990s, however, showed that the NSA suggestions actually strengthened DES, including the removal of a mathematical back door by a change to the design of the S-box (see "The Legacy of DES" by Bruce Schneier [2004]). In April 2021, the NSA declassified a fascinating historical paper titled "NSA Comes Out of the Closet: The Debate over Public Cryptography in the Inman Era" that appeared in Cryptologic Quarterly, Spring 1996.

    DES was defined in American National Standard X3.92 and three Federal Information Processing Standards (FIPS), all withdrawn in 2005:

    • FIPS PUB 46-3: DES (Archived file)
    • FIPS PUB 74: Guidelines for Implementing and Using the NBS Data Encryption Standard
    • FIPS PUB 81: DES Modes of Operation

    Information about vulnerabilities of DES can be obtained from the Electronic Frontier Foundation.

    Two important variants that strengthen DES are:

    • Triple-DES (3DES): A variant of DES that employs up to three 56-bit keys and makes three encryption/decryption passes over the block; 3DES is also described in FIPS PUB 46-3 and was an interim replacement to DES in the late-1990s and early-2000s.

    • DESX: A variant devised by Ron Rivest. By combining 64 additional key bits to the plaintext prior to encryption, effectively increases the keylength to 120 bits.

    More detail about DES, 3DES, and DESX can be found below in Section 5.4.

  • Advanced Encryption Standard (AES): In 1997, NIST initiated a very public, 4-1/2 year process to develop a new secure cryptosystem for U.S. government applications (as opposed to the very closed process in the adoption of DES 25 years earlier). The result, the Advanced Encryption Standard, became the official successor to DES in December 2001. AES uses an SKC scheme called Rijndael, a block cipher designed by Belgian cryptographers Joan Daemen and Vincent Rijmen. The algorithm can use a variable block length and key length; the latest specification allowed any combination of keys lengths of 128, 192, or 256 bits and blocks of length 128, 192, or 256 bits. NIST initially selected Rijndael in October 2000 and formal adoption as the AES standard came in December 2001. FIPS PUB 197 describes a 128-bit block cipher employing a 128-, 192-, or 256-bit key. AES is also part of the NESSIE approved suite of protocols. (See also the entries for CRYPTEC and NESSIE Projects in Table 3.)

    The AES process and Rijndael algorithm are described in more detail below in Section 5.9.

  • CAST-128/256: CAST-128 (aka CAST5), described in Request for Comments (RFC) 2144, is a DES-like substitution-permutation crypto algorithm, employing a 128-bit key operating on a 64-bit block. CAST-256 (aka CAST6), described in RFC 2612, is an extension of CAST-128, using a 128-bit block size and a variable length (128, 160, 192, 224, or 256 bit) key. CAST is named for its developers, Carlisle Adams and Stafford Tavares, and is available internationally. CAST-256 was one of the Round 1 algorithms in the AES process.

  • International Data Encryption Algorithm (IDEA): Secret-key cryptosystem written by Xuejia Lai and James Massey, in 1992 and patented by Ascom; a 64-bit SKC block cipher using a 128-bit key.

  • Rivest Ciphers (aka Ron's Code): Named for Ron Rivest, a series of SKC algorithms.

    • RC1: Designed on paper but never implemented.

    • RC2: A 64-bit block cipher using variable-sized keys designed to replace DES. It's code has not been made public although many companies have licensed RC2 for use in their products. Described in RFC 2268.

    • RC3: Found to be breakable during development.

    • RC4: A stream cipher using variable-sized keys; it is widely used in commercial cryptography products. An update to RC4, called Spritz (see also this article), was designed by Rivest and Jacob Schuldt. More detail about RC4 (and a little about Spritz) can be found below in Section 5.13.

    • RC5: A block-cipher supporting a variety of block sizes (32, 64, or 128 bits), key sizes, and number of encryption passes over the data. Described in RFC 2040.

    • RC6: A 128-bit block cipher based upon, and an improvement over, RC5; RC6 was one of the AES Round 2 algorithms.

  • Blowfish: A symmetric 64-bit block cipher invented by Bruce Schneier; optimized for 32-bit processors with large data caches, it is significantly faster than DES on a Pentium/PowerPC-class machine. Key lengths can vary from 32 to 448 bits in length. Blowfish, available freely and intended as a substitute for DES or IDEA, is in use in a large number of products.

  • Twofish: A 128-bit block cipher using 128-, 192-, or 256-bit keys. Designed to be highly secure and highly flexible, well-suited for large microprocessors, 8-bit smart card microprocessors, and dedicated hardware. Designed by a team led by Bruce Schneier and was one of the Round 2 algorithms in the AES process.

  • Threefish: A large block cipher, supporting 256-, 512-, and 1024-bit blocks and a key size that matches the block size; by design, the block/key size can grow in increments of 128 bits. Threefish only uses XOR operations, addition, and rotations of 64-bit words; the design philosophy is that an algorithm employing many computationally simple rounds is more secure than one employing highly complex — albeit fewer — rounds. The specification for Threefish is part of the Skein Hash Function Family documentation.

  • Anubis: Anubis is a block cipher, co-designed by Vincent Rijmen who was one of the designers of Rijndael. Anubis is a block cipher, performing substitution-permutation operations on 128-bit blocks and employing keys of length 128 to 3200 bits (in 32-bit increments). Anubis works very much like Rijndael. Although submitted to the NESSIE project, it did not make the final cut for inclusion.

  • ARIA: A 128-bit block cipher employing 128-, 192-, and 256-bit keys to encrypt 128-bit blocks in 12, 14, and 16 rounds, depending on the key size. Developed by large group of researchers from academic institutions, research institutes, and federal agencies in South Korea in 2003, and subsequently named a national standard. Described in RFC 5794.

  • Camellia: A secret-key, block-cipher crypto algorithm developed jointly by Nippon Telegraph and Telephone (NTT) Corp. and Mitsubishi Electric Corporation (MEC) in 2000. Camellia has some characteristics in common with AES: a 128-bit block size, support for 128-, 192-, and 256-bit key lengths, and suitability for both software and hardware implementations on common 32-bit processors as well as 8-bit processors (e.g., smart cards, cryptographic hardware, and embedded systems). Also described in RFC 3713. Camellia's application in IPsec is described in RFC 4312 and application in OpenPGP in RFC 5581. Camellia is part of the NESSIE suite of protocols.

  • CLEFIA: Described in RFC 6114, CLEFIA is a 128-bit block cipher employing key lengths of 128, 192, and 256 bits (which is compatible with AES). The CLEFIA algorithm was first published in 2007 by Sony Corporation. CLEFIA is one of the new-generation lightweight blockcipher algorithms designed after AES, offering high performance in software and hardware as well as a lightweight implementation in hardware.

  • FFX-A2 and FFX-A10: FFX (Format-preserving, Feistel-based encryption) is a type of Format Preserving Encryption (FPE) scheme that is designed so that the ciphertext has the same format as the plaintext. FPE schemes are used for such purposes as encrypting social security numbers, credit card numbers, limited size protocol traffic, etc.; this means that an encrypted social security number, for example, would still be a nine-digit string. FFX can theoretically encrypt strings of arbitrary length, although it is intended for message sizes smaller than that of AES-128 (2128 points). The FFX version 1.1 specification describes FFX-A2 and FFX-A10, which are intended for 8-128 bit binary strings or 4-36 digit decimal strings.

  • GSM (Global System for Mobile Communications, originally Groupe Spécial Mobile) encryption: GSM mobile phone systems use several stream ciphers for over-the-air communication privacy. A5/1 was developed in 1987 for use in Europe and the U.S. A5/2, developed in 1989, is a weaker algorithm and intended for use outside of Europe and the U.S. Significant flaws were found in both ciphers after the "secret" specifications were leaked in 1994, however, and A5/2 has been withdrawn from use. The newest version, A5/3, employs the KASUMI block cipher. NOTE: Unfortunately, although A5/1 has been repeatedly "broken" (e.g., see "Secret code protecting cellphone calls set loose" [2009] and "Cellphone snooping now easier and cheaper than ever" [2011]), this encryption scheme remains in widespread use, even in 3G and 4G mobile phone networks. Use of this scheme is reportedly one of the reasons that the National Security Agency (NSA) can easily decode voice and data calls over mobile phone networks.

  • GPRS (General Packet Radio Service) encryption: GSM mobile phone systems use GPRS for data applications, and GPRS uses a number of encryption methods, offering different levels of data protection. GEA/0 offers no encryption at all. GEA/1 and GEA/2 are proprietary stream ciphers, employing a 64-bit key and a 96-bit or 128-bit state, respectively. GEA/1 and GEA/2 are most widely used by network service providers today although both have been reportedly broken. GEA/3 is a 128-bit block cipher employing a 64-bit key that is used by some carriers; GEA/4 is a 128-bit clock cipher with a 128-bit key, but is not yet deployed.

  • KASUMI: A block cipher using a 128-bit key that is part of the Third-Generation Partnership Project (3gpp), formerly known as the Universal Mobile Telecommunications System (UMTS). KASUMI is the intended confidentiality and integrity algorithm for both message content and signaling data for emerging mobile communications systems.

  • KCipher-2: Described in RFC 7008, KCipher-2 is a stream cipher with a 128-bit key and a 128-bit initialization vector. Using simple arithmetic operations, the algorithms offers fast encryption and decryption by use of efficient implementations. KCipher-2 has been used for industrial applications, especially for mobile health monitoring and diagnostic services in Japan.

  • KHAZAD:KHAZAD is a so-called legacy block cipher, operating on 64-bit blocks à la older block ciphers such as DES and IDEA. KHAZAD uses eight rounds of substitution and permutation, with a 128-bit key.

  • KLEIN: Designed in 2011, KLEIN is a lightweight, 64-bit block cipher supporting 64-, 80- and 96-bit keys. KLEIN is designed for highly resource constrained devices such as wireless sensors and RFID tags.

  • Light Encryption Device (LED): Designed in 2011, LED is a lightweight, 64-bit block cipher supporting 64- and 128-bit keys. LED is designed for RFID tags, sensor networks, and other applications with devices constrained by memory or compute power.

  • MARS:MARS is a block cipher developed by IBM and was one of the five finalists in the AES development process. MARS employs 128-bit blocks and a variable key length from 128 to 448 bits. The MARS document stresses the ability of the algorithm's design for high speed, high security, and the ability to efficiently and effectively implement the scheme on a wide range of computing devices.

  • MISTY1: Developed at Mitsubishi Electric Corp., a block cipher using a 128-bit key and 64-bit blocks, and a variable number of rounds. Designed for hardware and software implementations, and is resistant to differential and linear cryptanalysis. Described in RFC 2994, MISTY1 is part of the NESSIE suite.

  • Salsa and ChaCha: Salsa20 is a stream cipher proposed for the eSTREAM project by Daniel Bernstein. Salsa20 uses a pseudorandom function based on 32-bit (whole word) addition, bitwise addition (XOR), and rotation operations, aka add-rotate-xor (ARX) operations. Salsa20 uses a 256-bit key although a 128-bit key variant also exists. In 2008, Bernstein published ChaCha, a new family of ciphers related to Salsa20. ChaCha20, originally defined in RFC 7539 (now obsoleted), is employed (with the Poly1305 authenticator) in Internet Engineering Task Force (IETF) protocols, most notably for IPsec and Internet Key Exchange (IKE), per RFC 7634, and Transaction Layer Security (TLS), per RFC 7905. In 2014, Google adopted ChaCha20/Poly1305 for use in OpenSSL, and they are also a part of OpenSSH. RFC 8439 replaces RFC 7539, and provides an implementation guide for both the ChaCha20 cipher and Poly1305 message authentication code, as well as the combined CHACHA20-POLY1305 Authenticated-Encryption with Associated-Data (AEAD) algorithm.

  • Secure and Fast Encryption Routine (SAFER): A series of block ciphers designed by James Massey for implementation in software and employing a 64-bit block. SAFER K-64, published in 1993, used a 64-bit key and SAFER K-128, published in 1994, employed a 128-bit key. After weaknesses were found, new versions were released called SAFER SK-40, SK-64, and SK-128, using 40-, 64-, and 128-bit keys, respectively. SAFER+ (1998) used a 128-bit block and was an unsuccessful candidate for the AES project; SAFER++ (2000) was submitted to the NESSIE project.

  • SEED: A block cipher using 128-bit blocks and 128-bit keys. Developed by the Korea Information Security Agency (KISA) and adopted as a national standard encryption algorithm in South Korea. Also described in RFC 4269.

  • Serpent:Serpent is another of the AES finalist algorithms. Serpent supports 128-, 192-, or 256-bit keys and a block size of 128 bits, and is a 32-round substitution–permutation network operating on a block of four 32-bit words. The Serpent developers opted for a high security margin in the design of the algorithm; they determined that 16 rounds would be sufficient against known attacks but require 32 rounds in an attempt to future-proof the algorithm.

  • SHACAL: SHACAL is a pair of block ciphers based upon the Secure Hash Algorithm (SHA) and the fact that SHA is, at heart, a compression algorithm. As a hash function, SHA repeatedly calls on a compression scheme to alter the state of the data blocks. While SHA (like other hash functions) is irreversible, the compression function can be used for encryption by maintaining appropriate state information. SHACAL-1 is based upon SHA-1 and uses a 160-bit block size while SHACAL-2 is based upon SHA-256 and employs a 256-bit block size; both support key sizes from 128 to 512 bits. SHACAL-2 is one of the NESSIE block ciphers.

  • Simon and Speck: Simon and Speck are a pair of lightweight block ciphers proposed by the NSA in 2013, designed for highly constrained software or hardware environments. (E.g., per the specification, AES requires 2400 gate equivalents and these ciphers require less than 2000.) While both cipher families perform well in both hardware and software, Simon has been optimized for high performance on hardware devices and Speck for performance in software. Both are Feistel ciphers and support ten combinations of block and key size:

  • Skipjack: SKC scheme proposed, along with the Clipper chip, as part of the never-implemented Capstone project. Although the details of the algorithm were never made public, Skipjack was a block cipher using an 80-bit key and 32 iteration cycles per 64-bit block. Capstone, proposed by NIST and the NSA as a standard for public and government use, met with great resistance by the crypto community largely because the design of Skipjack was classified (coupled with the key escrow requirement of the Clipper chip).

  • SM4: Formerly called SMS4, SM4 is a 128-bit block cipher using 128-bit keys and 32 rounds to process a block. Declassified in 2006, SM4 is used in the Chinese National Standard for Wireless Local Area Network (LAN) Authentication and Privacy Infrastructure (WAPI). SM4 had been a proposed cipher for the Institute of Electrical and Electronics Engineers (IEEE) 802.11i standard on security mechanisms for wireless LANs, but has yet to be accepted by the IEEE or International Organization for Standardization (ISO). SM4 is described in SMS4 Encryption Algorithm for Wireless Networks (translated by Whitfield Diffie and George Ledin, 2008) and at the SM4 (cipher) page. SM4 is issued by the Chinese State Cryptographic Authority as GM/T 0002-2012: SM4 (2012).

  • Tiny Encryption Algorithm (TEA): A family of block ciphers developed by Roger Needham and David Wheeler. TEA was originally developed in 1994, and employed a 128-bit key, 64-bit block, and 64 rounds of operation. To correct certain weaknesses in TEA, eXtended TEA (XTEA), aka Block TEA, was released in 1997. To correct weaknesses in XTEA and add versatility, Corrected Block TEA (XXTEA) was published in 1998. XXTEA also uses a 128-bit key, but block size can be any multiple of 32-bit words (with a minimum block size of 64 bits, or two words) and the number of rounds is a function of the block size (~52+6*words), as shown in Table 1.

  • Block Size
    2n
    Key Size
    mn
    Word Size
    n
    Key Words
    m
    Rounds
    T
    326416432
    4872
    96
    243
    4
    36
    36
    6496
    128
    323
    4
    42
    44
    9696
    144
    482
    3
    52
    54
    128128
    192
    256
    642
    3
    4
    68
    69
    72
  • TWINE: Designed by engineers at NEC in 2011, TWINE is a lightweight, 64-bit block cipher supporting 80- and 128-bit keys. TWINE's design goals included maintaining a small footprint in a hardware implementation (i.e., fewer than 2,000 gate equivalents) and small memory consumption in a software implementation.

Although not an SKC scheme, check out Section 5.17 about Shamir's Secret Sharing (SSS).

There are several other references that describe interesting algorithms and even SKC codes dating back decades. Two that leap to mind are the Crypto Museum's Crypto List and John J.G. Savard's (albeit old) A Cryptographic Compendium page.

3.2. Public Key Cryptography

Public key cryptography has been said to be the most significant new development in cryptography in the last 300-400 years. Modern PKC was first described publicly by Stanford University professor Martin Hellman and graduate student Whitfield Diffie in 1976. Their paper described a two-key crypto system in which two parties could engage in a secure communication over a non-secure communications channel without having to share a secret key.

PKC depends upon the existence of so-called one-way functions, or mathematical functions that are easy to compute whereas their inverse function is relatively difficult to compute. Let me give you two simple examples:

  1. Multiplication vs. factorization: Suppose you have two prime numbers, 3 and 7, and you need to calculate the product; it should take almost no time to calculate that value, which is 21. Now suppose, instead, that you have a number that is a product of two primes, 21, and you need to determine those prime factors. You will eventually come up with the solution but whereas calculating the product took milliseconds, factoring will take longer. The problem becomes much harder if we start with primes that have, say, 400 digits or so, because the product will have ~800 digits.
  2. Exponentiation vs. logarithms: Suppose you take the number 3 to the 6th power; again, it is relatively easy to calculate 36 = 729. But if you start with the number 729 and need to determine the two integers, x and y so that logx 729 = y, it will take longer to find the two values.

While the examples above are trivial, they do represent two of the functional pairs that are used with PKC; namely, the ease of multiplication and exponentiation versus the relative difficulty of factoring and calculating logarithms, respectively. The mathematical "trick" in PKC is to find a trap door in the one-way function so that the inverse calculation becomes easy given knowledge of some item of information.

Generic PKC employs two keys that are mathematically related although knowledge of one key does not allow someone to easily determine the other key. One key is used to encrypt the plaintext and the other key is used to decrypt the ciphertext. The important point here is that it does not matter which key is applied first, but that both keys are required for the process to work (Figure 1B). Because a pair of keys are required, this approach is also called asymmetric cryptography.

In PKC, one of the keys is designated the public key and may be advertised as widely as the owner wants. The other key is designated the private key and is never revealed to another party. It is straight-forward to send messages under this scheme. Suppose Alice wants to send Bob a message. Alice encrypts some information using Bob's public key; Bob decrypts the ciphertext using his private key. This method could be also used to prove who sent a message; Alice, for example, could encrypt some plaintext with her private key; when Bob decrypts using Alice's public key, he knows that Alice sent the message (authentication) and Alice cannot deny having sent the message (non-repudiation).

Public key cryptography algorithms that are in use today for key exchange or digital signatures include:

  • RSA: The first, and still most common, PKC implementation, named for the three MIT mathematicians who developed it — Ronald Rivest, Adi Shamir, and Leonard Adleman. RSA today is used in hundreds of software products and can be used for key exchange, digital signatures, or encryption of small blocks of data. RSA uses a variable size encryption block and a variable size key. The key-pair is derived from a very large number, n, that is the product of two prime numbers chosen according to special rules; these primes may be 100 or more digits in length each, yielding an n with roughly twice as many digits as the prime factors. The public key information includes n and a derivative of one of the factors of n; an attacker cannot determine the prime factors of n (and, therefore, the private key) from this information alone and that is what makes the RSA algorithm so secure. (Some descriptions of PKC erroneously state that RSA's safety is due to the difficulty in factoring large prime numbers. In fact, large prime numbers, like small prime numbers, only have two factors!) The ability for computers to factor large numbers, and therefore attack schemes such as RSA, is rapidly improving and systems today can find the prime factors of numbers with more than 200 digits. Nevertheless, if a large number is created from two prime factors that are roughly the same size, there is no known factorization algorithm that will solve the problem in a reasonable amount of time; a 2005 test to factor a 200-digit number took 1.5 years and over 50 years of compute time. In 2009, Kleinjung et al. reported that factoring a 768-bit (232-digit) RSA-768 modulus utilizing hundreds of systems took two years and they estimated that a 1024-bit RSA modulus would take about a thousand times as long. Even so, they suggested that 1024-bit RSA be phased out by 2013. (See the Wikipedia article on integer factorization.) Regardless, one presumed protection of RSA is that users can easily increase the key size to always stay ahead of the computer processing curve. As an aside, the patent for RSA expired in September 2000 which does not appear to have affected RSA's popularity one way or the other. A detailed example of RSA is presented below in Section 5.3.

  • Diffie-Hellman: After the RSA algorithm was published, Diffie and Hellman came up with their own algorithm. Diffie-Hellman is used for secret-key key exchange only, and not for authentication or digital signatures. More detail about Diffie-Hellman can be found below in Section 5.2.

  • Digital Signature Algorithm (DSA): The algorithm specified in NIST's Digital Signature Standard (DSS), provides digital signature capability for the authentication of messages. Described in FIPS PUB 186-4.

  • ElGamal: Designed by Taher Elgamal, ElGamal is a PKC system similar to Diffie-Hellman and used for key exchange. ElGamal is used in some later version of Pretty Good Privacy (PGP) as well as GNU Privacy Guard (GPG) and other cryptosystems.

  • Elliptic Curve Cryptography (ECC): A PKC algorithm based upon elliptic curves. ECC can offer levels of security with small keys comparable to RSA and other PKC methods. It was designed for devices with limited compute power and/or memory, such as smartcards and PDAs. More detail about ECC can be found below in Section 5.8. Other references include the Elliptic Curve Cryptography page and the Online ECC Tutorial page, both from Certicom. See also RFC 6090 for a review of fundamental ECC algorithms and The Elliptic Curve Digital Signature Algorithm (ECDSA) for details about the use of ECC for digital signatures.

  • Identity-Based Encryption (IBE): IBE is a novel scheme first proposed by Adi Shamir in 1984. It is a PKC-based key authentication system where the public key can be derived from some unique information based upon the user's identity, allowing two users to exchange encrypted messages without having an a priori relationship. In 2001, Dan Boneh (Stanford) and Matt Franklin (U.C., Davis) developed a practical implementation of IBE based on elliptic curves and a mathematical construct called the Weil Pairing. In that year, Clifford Cocks (GCHQ) also described another IBE solution based on quadratic residues in composite groups. RFC 5091: Identity-Based Cryptography Standard (IBCS) #1 describes an implementation of IBE using Boneh-Franklin (BF) and Boneh-Boyen (BB1) Identity-based Encryption. More detail about Identity-Based Encryption can be found below in Section 5.16.

  • Public Key Cryptography Standards (PKCS): A set of interoperable standards and guidelines for public key cryptography, designed by RSA Data Security Inc. (These documents are no longer easily available; all links in this section are from archive.org.)

  • Cramer-Shoup: A public key cryptosystem proposed by R. Cramer and V. Shoup of IBM in 1998.

  • Key Exchange Algorithm (KEA): A variation on Diffie-Hellman; proposed as the key exchange method for the NIST/NSA Capstone project.

  • LUC: A public key cryptosystem designed by P.J. Smith and based on Lucas sequences. Can be used for encryption and signatures, using integer factoring.

  • McEliece: A public key cryptosystem based on algebraic coding theory.

For additional information on PKC algorithms, see "Public Key Encryption" (Chapter 8) in Handbook of Applied Cryptography, by A. Menezes, P. van Oorschot, and S. Vanstone (CRC Press, 1996).


A digression: Who invented PKC? I tried to be careful in the first paragraph of this section to state that Diffie and Hellman "first described publicly" a PKC scheme. Although I have categorized PKC as a two-key system, that has been merely for convenience; the real criteria for a PKC scheme is that it allows two parties to exchange a secret even though the communication with the shared secret might be overheard. There seems to be no question that Diffie and Hellman were first to publish; their method is described in the classic paper, "New Directions in Cryptography," published in the November 1976 issue of IEEE Transactions on Information Theory (IT-22(6), 644-654). As shown in Section 5.2, Diffie-Hellman uses the idea that finding logarithms is relatively harder than performing exponentiation. And, indeed, it is the precursor to modern PKC which does employ two keys. Rivest, Shamir, and Adleman described an implementation that extended this idea in their paper, "A Method for Obtaining Digital Signatures and Public Key Cryptosystems," published in the February 1978 issue of the Communications of the ACM (CACM), (21(2), 120-126). Their method, of course, is based upon the relative ease of finding the product of two large prime numbers compared to finding the prime factors of a large number.

Diffie and Hellman (and other sources) credit Ralph Merkle with first describing a public key distribution system that allows two parties to share a secret, although it was not a two-key system, per se. A Merkle Puzzle works where Alice creates a large number of encrypted keys, sends them all to Bob so that Bob chooses one at random and then lets Alice know which he has selected. An eavesdropper (Eve) will see all of the keys but can't learn which key Bob has selected (because he has encrypted the response with the chosen key). In this case, Eve's effort to break in is the square of the effort of Bob to choose a key. While this difference may be small it is often sufficient. Merkle apparently took a computer science course at UC Berkeley in 1974 and described his method, but had difficulty making people understand it; frustrated, he dropped the course. Meanwhile, he submitted the paper "Secure Communication Over Insecure Channels," which was published in the CACM in April 1978; Rivest et al.'s paper even makes reference to it. Merkle's method certainly wasn't published first, but he is often credited to have had the idea first.

An interesting question, maybe, but who really knows? For some time, it was a quiet secret that a team at the UK's Government Communications Headquarters (GCHQ) had first developed PKC in the early 1970s. Because of the nature of the work, GCHQ kept the original memos classified. In 1997, however, the GCHQ changed their posture when they realized that there was nothing to gain by continued silence. Documents show that a GCHQ mathematician named James Ellis started research into the key distribution problem in 1969 and that by 1975, James Ellis, Clifford Cocks, and Malcolm Williamson had worked out all of the fundamental details of PKC, yet couldn't talk about their work. (They were, of course, barred from challenging the RSA patent!) By 1999, Ellis, Cocks, and Williamson began to get their due credit in a break-through article in WIRED Magazine. And the National Security Agency (NSA) claims to have knowledge of this type of algorithm as early as 1966. For some additional insight on who knew what when, see Steve Bellovin's "The Prehistory of Public Key Cryptography."


3.3. Hash Functions

Hash functions, also called message digests and one-way encryption, are algorithms that, in essence, use no key (Figure 1C). Instead, a fixed-length hash value is computed based upon the plaintext that makes it impossible for either the contents or length of the plaintext to be recovered. Hash algorithms are typically used to provide a digital fingerprint of a file's contents, often used to ensure that the file has not been altered by an intruder or virus. Hash functions are also commonly employed by many operating systems to encrypt passwords. Hash functions, then, provide a mechanism to ensure the integrity of a file.

Hash functions are also designed so that small changes in the input produce significant differences in the hash value, for example:

Hash string 1: The quick brown fox jumps over the lazy dog
Hash string 2: The quick brown fox jumps over the lazy dog.

MD5 [hash string 1] = 37c4b87edffc5d198ff5a185cee7ee09
MD5 [hash string 2] = 0d7006cd055e94cf614587e1d2ae0c8e

SHA1 [hash string 1] = be417768b5c3c5c1d9bcb2e7c119196dd76b5570
SHA1 [hash string 2] = 9c04cd6372077e9b11f70ca111c9807dc7137e4b

RIPEMD160 [hash string 1] = ee061f0400729d0095695da9e2c95168326610ff
RIPEMD160 [hash string 2] = 99b90925a0116c302984211dbe25b5343be9059e


Let me reiterate that hashes are one-way encryption. You cannot take a hash and "decrypt" it to find the original string that created it, despite the many web sites that claim or suggest otherwise, such as CrackStation, Hashes.com, MD5 Online, md5thiscracker, OnlineHashCrack, and RainbowCrack.

Note that these sites search databases and/or use rainbow tables to find a suitable string that produces the hash in question but one can't definitively guarantee what string originally produced the hash. This is an important distinction. Suppose that you want to crack someone's password, where the hash of the password is stored on the server. Indeed, all you then need is a string that produces the correct hash and you're in! However, you cannot prove that you have discovered the user's password, only a "duplicate key."


Hash algorithms in common use today include:

  • Message Digest (MD) algorithms: A series of byte-oriented algorithms that produce a 128-bit hash value from an arbitrary-length message.

    • MD2 (RFC 1319): Designed for systems with limited memory, such as smart cards. (MD2 has been relegated to historical status, per RFC 6149.)

    • MD4 (RFC 1320): Developed by Rivest, similar to MD2 but designed specifically for fast processing in software. (MD4 has been relegated to historical status, per RFC 6150.)

    • MD5 (RFC 1321): Also developed by Rivest after potential weaknesses were reported in MD4; this scheme is similar to MD4 but is slower because more manipulation is made to the original data. MD5 has been implemented in a large number of products although several weaknesses in the algorithm were demonstrated by German cryptographer Hans Dobbertin in 1996 ("Cryptanalysis of MD5 Compress"). (Updated security considerations for MD5 can be found in RFC 6151.)

  • Secure Hash Algorithm (SHA): Algorithm for NIST's Secure Hash Standard (SHS), described in FIPS PUB 180-4 The status of NIST hash algorithms can be found on their "Policy on Hash Functions" page.

    • SHA-1 produces a 160-bit hash value and was originally published as FIPS PUB 180-1 and RFC 3174. SHA-1 was deprecated by NIST as of the end of 2013 although it is still widely used.

    • SHA-2, originally described in FIPS PUB 180-2 and eventually replaced by FIPS PUB 180-3 (and FIPS PUB 180-4), comprises five algorithms in the SHS: SHA-1 plus SHA-224, SHA-256, SHA-384, and SHA-512 which can produce hash values that are 224, 256, 384, or 512 bits in length, respectively. SHA-2 recommends use of SHA-1, SHA-224, and SHA-256 for messages less than 264 bits in length, and employs a 512 bit block size; SHA-384 and SHA-512 are recommended for messages less than 2128 bits in length, and employs a 1,024 bit block size. FIPS PUB 180-4 also introduces the concept of a truncated hash in SHA-512/t, a generic name referring to a hash value based upon the SHA-512 algorithm that has been truncated to t bits; SHA-512/224 and SHA-512/256 are specifically described. SHA-224, -256, -384, and -512 are also described in RFC 4634.

    • SHA-3 is the current SHS algorithm. Although there had not been any successful attacks on SHA-2, NIST decided that having an alternative to SHA-2 using a different algorithm would be prudent. In 2007, they launched a SHA-3 Competition to find that alternative; a list of submissions can be found at The SHA-3 Zoo. In 2012, NIST announced that after reviewing 64 submissions, the winner was Keccak (pronounced "catch-ack"), a family of hash algorithms based on sponge functions. The NIST version can support hash output sizes of 256 and 512 bits.

  • RIPEMD: A series of message digests that initially came from the RIPE (RACE Integrity Primitives Evaluation) project. RIPEMD-160 was designed by Hans Dobbertin, Antoon Bosselaers, and Bart Preneel, and optimized for 32-bit processors to replace the then-current 128-bit hash functions. Other versions include RIPEMD-256, RIPEMD-320, and RIPEMD-128.

  • eD2k: Named for the EDonkey2000 Network (eD2K), the eD2k hash is a root hash of an MD4 hash list of a given file. A root hash is used on peer-to-peer file transfer networks, where a file is broken into chunks; each chunk has its own MD4 hash associated with it and the server maintains a file that contains the hash list of all of the chunks. The root hash is the hash of the hash list file.

  • HAVAL (HAsh of VAriable Length): Designed by Y. Zheng, J. Pieprzyk and J. Seberry, a hash algorithm with many levels of security. HAVAL can create hash values that are 128, 160, 192, 224, or 256 bits in length. More details can be found in "HAVAL - A one-way hashing algorithm with variable length output" by Zheng, Pieprzyk, and Seberry (AUSCRYPT '92).

  • The Skein Hash Function Family: The Skein Hash Function Family was proposed to NIST in their 2010 hash function competition. Skein is fast due to using just a few simple computational primitives, secure, and very flexible — per the specification, it can be used as a straight-forward hash, MAC, HMAC, digital signature hash, key derivation mechanism, stream cipher, or pseuo-random number generator. Skein supports internal state sizes of 256, 512 and 1024 bits, and arbitrary output lengths.

  • SM3: SM3 is a 256-bit hash function operating on 512-bit input blocks. Part of a Chinese National Standard, SM3 is issued by the Chinese State Cryptographic Authority as GM/T 0004-2012: SM3 cryptographic hash algorithm (2012) and GB/T 32905-2016: Information security techniques—SM3 cryptographic hash algorithm (2016). More information can also be found at the SM3 (hash function) page.

  • Tiger: Designed by Ross Anderson and Eli Biham, Tiger is designed to be secure, run efficiently on 64-bit processors, and easily replace MD4, MD5, SHA and SHA-1 in other applications. Tiger/192 produces a 192-bit output and is compatible with 64-bit architectures; Tiger/128 and Tiger/160 produce a hash of length 128 and 160 bits, respectively, to provide compatibility with the other hash functions mentioned above.

  • Whirlpool: Designed by V. Rijmen (co-inventor of Rijndael) and P.S.L.M. Barreto, Whirlpool is one of two hash functions endorsed by the NESSIE competition (the other being SHA). Whirlpool operates on messages less than 2256 bits in length and produces a message digest of 512 bits. The design of this hash function is very different than that of MD5 and SHA-1, making it immune to the types of attacks that succeeded on those hashes.

Readers might be interested in HashCalc, a Windows-based program that calculates hash values using a dozen algorithms, including MD5, SHA-1 and several variants, RIPEMD-160, and Tiger. Command line utilities that calculate hash values include sha_verify by Dan Mares (Windows; supports MD5, SHA-1, SHA-2) and md5deep (cross-platform; supports MD5, SHA-1, SHA-256, Tiger, and Whirlpool).


A digression on hash collisions. Hash functions are sometimes misunderstood and some sources claim that no two files can have the same hash value. This is in theory, if not in fact, incorrect. Consider a hash function that provides a 128-bit hash value. There are, then, 2128 possible hash values. But there are an infinite number of possible files and ∞ >> 2128. Therefore, there have to be multiple files — in fact, there have to be an infinite number of files! — that have the same 128-bit hash value. (Now, while even this is theoretically correct, it is not true in practice because hash algorithms are designed to work with a limited message size, as mentioned above. For example, SHA-1, SHA-224, and SHA-256 produce hash values that are 160, 224, and 256 bits in length, respectively, and limit the message length to less than 264 bits; SHA-384 and all SHA-256 variants limit the message length to less than 2128 bits. Nevertheless, hopefully you get my point — and, alas, even if you don't, do know that there are multiple files that have the same MD5 or SHA-1 hash values.)

The difficulty is not necessarily in finding two files with the same hash, but in finding a second file that has the same hash value as a given first file. Consider this example. A human head has, generally, no more than ~150,000 hairs. Since there are more than 7 billion people on earth, we know that there are a lot of people with the same number of hairs on their head. Finding two people with the same number of hairs, then, would be relatively simple. The harder problem is choosing one person (say, you, the reader) and then finding another person who has the same number of hairs on their head as you have on yours.

This is somewhat similar to the Birthday Problem. We know from probability that if you choose a random group of ~23 people, the probability is about 50% that two will share a birthday (the probability goes up to 99.9% with a group of 70 people). However, if you randomly select one person in a group of 23 and try to find a match to that person, the probability is only about 6% of finding a match; you'd need a group of 253 for a 50% probability of a shared birthday to one of the people chosen at random (and a group of more than 4,000 to obtain a 99.9% probability).

What is hard to do, then, is to try to create a file that matches a given hash value so as to force a hash value collision — which is the reason that hash functions are used extensively for information security and computer forensics applications. Alas, researchers as far back as 2004 found that practical collision attacks could be launched on MD5, SHA-1, and other hash algorithms and, today, it is generally recognized that MD5 and SHA-1 are pretty much broken. Readers interested in this problem should read the following:

  • AccessData. (2006, April). MD5 Collisions: The Effect on Computer Forensics. AccessData White Paper.
  • Burr, W. (2006, March/April). Cryptographic hash standards: Where do we go from here?IEEE Security & Privacy, 4(2), 88-91.
  • Dwyer, D. (2009, June 3). SHA-1 Collision Attacks Now 252. SecureWorks Research blog.
  • Gutman, P., Naccache, D., & Palmer, C.C. (2005, May/June). When hashes collide. IEEE Security & Privacy, 3(3), 68-71.
  • Kessler, G.C. (2016). The Impact of MD5 File Hash Collisions on Digital Forensic Imaging. Journal of Digital Forensics, Security & Law, 11(4), 129-138.
  • Kessler, G.C. (2016). The Impact of SHA-1 File Hash Collisions on Digital Forensic Imaging: A Follow-Up Experiment. Journal of Digital Forensics, Security & Law, 11(4), 139-148.
  • Klima, V. (2005, March). Finding MD5 Collisions - a Toy For a Notebook.
  • Lee, R. (2009, January 7). Law Is Not A Science: Admissibility of Computer Evidence and MD5 Hashes. SANS Computer Forensics blog.
  • Leurent, G. & Peyrin, T. (2020, January). SHA-1 is a Shambles: First Chosen-Prefix Collision on SHA-1 and Application to the PGP Web of Trust. Real World Crypto 2020.
  • Leurent, G. & Peyrin, T. (2020, January). SHA-1 is a Shambles: First Chosen-Prefix Collision on SHA-1 and Application to the PGP Web of Trust.(paper)
  • Stevens, M., Bursztein, E., Karpman, P., Albertini, A., & Markov, Y. (2017). The first collision for full SHA-1.
  • Stevens, M., Karpman, P., & Peyrin, T. (2015, October 8). Freestart collision on full SHA-1. Cryptology ePrint Archive, Report 2015/967.
  • Thompson, E. (2005, February). MD5 collisions and the impact on computer forensics. Digital Investigation, 2(1), 36-40.
  • Wang, X., Feng, D., Lai, X., & Yu, H. (2004, August). Collisions for Hash Functions MD4, MD5, HAVAL-128 and RIPEMD.
  • Wang, X., Yin, Y.L., & Yu, H. (2005, February 13). Collision Search Attacks on SHA1.

Readers are also referred to the Eindhoven University of Technology HashClash Project Web site. for For additional information on hash functions, see David Hopwood's MessageDigest Algorithms page and Peter Selinger's MD5 Collision Demo page. For historical purposes, take a look at the situation with hash collisions, circa 2005, in RFC 4270.

In October 2015, the SHA-1 Freestart Collision was announced; see a report by Bruce Schneier and the developers of the attack (as well as the paper above by Stevens et al. (2015)). In February 2017, the first SHA-1 collision was announced on the Google Security Blog and Centrum Wiskunde & Informatica's Shattered page. See also the paper by Stevens et al. (2017), listed above. If ths isn't enough, see the SHA-1 is a Shambles Web page and the Leurent & Peyrin paper, listed above.

For an interesting twist on this discussion, read about the Nostradamus attack reported at Predicting the winner of the 2008 US Presidential Elections using a Sony PlayStation 3 (by M. Stevens, A.K. Lenstra, and B. de Weger, November 2007).


Finally, note that certain extensions of hash functions are used for a variety of information security and digital forensics applications, such as:

  • Hash libraries, aka hashsets, are sets of hash values corresponding to known files. A hashset containing the hash values of all files known to be a part of a given operating system, for example, could form a set of known good files, and could be ignored in an investigation for malware or other suspicious file, whereas as hash library of known child pornographic images could form a set of known bad files and be the target of such an investigation.
  • Rolling hashes refer to a set of hash values that are computed based upon a fixed-length "sliding window" through the input. As an example, a hash value might be computed on bytes 1-10 of a file, then on bytes 2-11, 3-12, 4-13, etc.
  • Fuzzy hashes are an area of intense research and represent hash values that represent two inputs that are similar. Fuzzy hashes are used to detect documents, images, or other files that are close to each other with respect to content. See "Fuzzy Hashing" by Jesse Kornblum for a good treatment of this topic.

3.4. Why Three Encryption Techniques?

So, why are there so many different types of cryptographic schemes? Why can't we do everything we need with just one?

The answer is that each scheme is optimized for some specific cryptographic application(s). Hash functions, for example, are well-suited for ensuring data integrity because any change made to the contents of a message will result in the receiver calculating a different hash value than the one placed in the transmission by the sender. Since it is highly unlikely that two different messages will yield the same hash value, data integrity is ensured to a high degree of confidence.

Secret key cryptography, on the other hand, is ideally suited to encrypting messages, thus providing privacy and confidentiality. The sender can generate a session key on a per-message basis to encrypt the message; the receiver, of course, needs the same session key in order to decrypt the message.

Key exchange, of course, is a key application of public key cryptography (no pun intended). Asymmetric schemes can also be used for non-repudiation and user authentication; if the receiver can obtain the session key encrypted with the sender's private key, then only this sender could have sent the message. Public key cryptography could, theoretically, also be used to encrypt messages although this is rarely done because secret key cryptography values can generally be computed about 1000 times faster than public key cryptography values.

FIGURE 4: Use of the three cryptographic techniques for secure communication.


Figure 4 puts all of this together and shows how a hybrid cryptographic scheme combines all of these functions to form a secure transmission comprising a digital signature and digital envelope. In this example, the sender of the message is Alice and the receiver is Bob.

A digital envelope comprises an encrypted message and an encrypted session key. Alice uses secret key cryptography to encrypt her message using the session key, which she generates at random with each session. Alice then encrypts the session key using Bob's public key. The encrypted message and encrypted session key together form the digital envelope. Upon receipt, Bob recovers the session secret key using his private key and then decrypts the encrypted message.

The digital signature is formed in two steps. First, Alice computes the hash value of her message; next, she encrypts the hash value with her private key. Upon receipt of the digital signature, Bob recovers the hash value calculated by Alice by decrypting the digital signature with Alice's public key. Bob can then apply the hash function to Alice's original message, which he has already decrypted (see previous paragraph). If the resultant hash value is not the same as the value supplied by Alice, then Bob knows that the message has been altered; if the hash values are the same, Bob should believe that the message he received is identical to the one that Alice sent.

This scheme also provides nonrepudiation since it proves that Alice sent the message; if the hash value recovered by Bob using Alice's public key proves that the message has not been altered, then only Alice could have created the digital signature. Bob also has proof that he is the intended receiver; if he can correctly decrypt the message, then he must have correctly decrypted the session key meaning that his is the correct private key.

This diagram purposely suggests a cryptosystem where the session key is used for just a single session. Even if this session key is somehow broken, only this session will be compromised; the session key for the next session is not based upon the key for this session, just as this session's key was not dependent on the key from the previous session. This is known as Perfect Forward Secrecy; you might lose one session key due to a compromise but you won't lose all of them. (This was an issue in the 2014 OpenSSL vulnerability known as Heartbleed.)

3.5. The Significance of Key Length

In a 1998 article in the industry literature, a writer made the claim that 56-bit keys did not provide as adequate protection for DES at that time as they did in 1975 because computers were 1000 times faster in 1998 than in 1975. Therefore, the writer went on, we needed 56,000-bit keys in 1998 instead of 56-bit keys to provide adequate protection. The conclusion was then drawn that because 56,000-bit keys are infeasible (true), we should accept the fact that we have to live with weak cryptography (false!). The major error here is that the writer did not take into account that the number of possible key values double whenever a single bit is added to the key length; thus, a 57-bit key has twice as many values as a 56-bit key (because 257 is two times 256). In fact, a 66-bit key would have 1024 times more values than a 56-bit key.

But this does bring up the question — "What is the significance of key length as it affects the level of protection?"

In cryptography, size does matter. The larger the key, the harder it is to crack a block of encrypted data. The reason that large keys offer more protection is almost obvious; computers have made it easier to attack ciphertext by using brute force methods rather than by attacking the mathematics (which are generally well-known anyway). With a brute force attack, the attacker merely generates every possible key and applies it to the ciphertext. Any resulting plaintext that makes sense offers a candidate for a legitimate key. This was the basis, of course, of the EFF's attack on DES.

Until the mid-1990s or so, brute force attacks were beyond the capabilities of computers that were within the budget of the attacker community. By that time, however, significant compute power was typically available and accessible. General-purpose computers such as PCs were already being used for brute force attacks. For serious attackers with money to spend, such as some large companies or governments, Field Programmable Gate Array (FPGA) or Application-Specific Integrated Circuits (ASIC) technology offered the ability to build specialized chips that could provide even faster and cheaper solutions than a PC. As an example, the AT&T Optimized Reconfigurable Cell Array (ORCA) FPGA chip cost about $200 and could test 30 million DES keys per second, while a $10 ASIC chip could test 200 million DES keys per second; compare that to a PC which might be able to test 40,000 keys per second. Distributed attacks, harnessing the power of up to tens of thousands of powerful CPUs, are now commonly employed to try to brute-force crypto keys.

Type of AttackerBudgetToolTime and Cost
Per Key Recovered
Key Length Needed
For Protection
In Late-1995
40 bits56 bits
Pedestrian HackerTinyScavenged
computer
time
1 weekInfeasible45
$400FPGA5 hours
($0.08)
38 years
($5,000)
50
Small Business$10,000FPGA12 minutes
($0.08)
18 months
($5,000)
55
Corporate Department$300KFPGA24 seconds
($0.08)
19 days
($5,000)
60
ASIC0.18 seconds
($0.001)
3 hours
($38)
Big Company$10MFPGA7 seconds
($0.08)
13 hours
($5,000)
70
ASIC0.005 seconds
($0.001)
6 minutes
($38)
Intelligence Agency$300MASIC0.0002 seconds
($0.001)
12 seconds
($38)
75

Table 2 — from a 1996 article discussing both why exporting 40-bit keys was, in essence, no crypto at all and why DES' days were numbered — shows what DES key sizes were needed to protect data from attackers with different time and financial resources. This information was not merely academic; one of the basic tenets of any security system is to have an idea of what you are protecting and from whom are you protecting it! The table clearly shows that a 40-bit key was essentially worthless against even the most unsophisticated attacker. On the other hand, 56-bit keys were fairly strong unless you might be subject to some pretty serious corporate or government espionage. But note that even 56-bit keys were clearly on the decline in their value and that the times in the table were worst cases.

So, how big is big enough? DES, invented in 1975, was still in use at the turn of the century, nearly 25 years later. If we take that to be a design criteria (i.e., a 20-plus year lifetime) and we believe Moore's Law ("computing power doubles every 18 months"), then a key size extension of 14 bits (i.e., a factor of more than 16,000) should be adequate. The 1975 DES proposal suggested 56-bit keys; by 1995, a 70-bit key would have been required to offer equal protection and an 85-bit key necessary by 2015.

A 256- or 512-bit SKC key will probably suffice for some time because that length keeps us ahead of the brute force capabilities of the attackers. Note that while a large key is good, a huge key may not always be better; for example, expanding PKC keys beyond the current 2048- or 4096-bit lengths doesn't add any necessary protection at this time. Weaknesses in cryptosystems are largely based upon key management rather than weak keys.

Much of the discussion above, including the table, is based on the paper "Minimal Key Lengths for Symmetric Ciphers to Provide Adequate Commercial Security" by M. Blaze, W. Diffie, R.L. Rivest, B. Schneier, T. Shimomura, E. Thompson, and M. Wiener (1996).

The most effective large-number factoring methods today use a mathematical Number Field Sieve to find a certain number of relationships and then uses a matrix operation to solve a linear equation to produce the two prime factors. The sieve step actually involves a large number of operations that can be performed in parallel; solving the linear equation, however, requires a supercomputer. Indeed, finding the solution to the RSA-140 challenge in February 1999 — factoring a 140-digit (465-bit) prime number — required 200 computers across the Internet about 4 weeks for the first step and a Cray computer 100 hours and 810 MB of memory to do the second step.

In early 1999, Shamir (of RSA fame) described a new machine that could increase factorization speed by 2-3 orders of magnitude. Although no detailed plans were provided nor is one known to have been built, the concepts of TWINKLE (The Weizmann Institute Key Locating Engine) could result in a specialized piece of hardware that would cost about $5000 and have the processing power of 100-1000 PCs. There still appear to be many engineering details that have to be worked out before such a machine could be built. Furthermore, the hardware improves the sieve step only; the matrix operation is not optimized at all by this design and the complexity of this step grows rapidly with key length, both in terms of processing time and memory requirements. Nevertheless, this plan conceptually puts 512-bit keys within reach of being factored. Although most PKC schemes allow keys that are 1024 bits and longer, Shamir claims that 512-bit RSA keys "protect 95% of today's E-commerce on the Internet." (See Bruce Schneier's Crypto-Gram (May 15, 1999) for more information.)

It is also interesting to note that while cryptography is good and strong cryptography is better, long keys may disrupt the nature of the randomness of data files. Shamir and van Someren ("Playing hide and seek with stored keys") have noted that a new generation of viruses can be written that will find files encrypted with long keys, making them easier to find by intruders and, therefore, more prone to attack.

Finally, U.S. government policy has tightly controlled the export of crypto products since World War II. Until the mid-1990s, export outside of North America of cryptographic products using keys greater than 40 bits in length was prohibited, which made those products essentially worthless in the marketplace, particularly for electronic commerce; today, crypto products are widely available on the Internet without restriction. The U.S. Department of Commerce Bureau of Industry and Security maintains an Encryption FAQ web page with more information about the current state of encryption registration.


Without meaning to editorialize too much in this tutorial, a bit of historical context might be helpful. In the mid-1990s, the U.S. Department of Commerce still classified cryptography as a munition and limited the export of any products that contained crypto. For that reason, browsers in the 1995 era, such as Internet Explorer and Netscape, had a domestic version with 128-bit encryption (downloadable only in the U.S.) and an export version with 40-bit encryption. Many cryptographers felt that the export limitations should be lifted because they only applied to U.S. products and seemed to have been put into place by policy makers who believed that only the U.S. knew how to build strong crypto algorithms, ignoring the work ongoing in Australia, Canada, Israel, South Africa, the U.K., and other locations in the 1990s. Those restrictions were lifted by 1996 or 1997, but there is still a prevailing attitude, apparently, that U.S. crypto algorithms are the only strong ones around; consider Bruce Schneier's blog in June 2016 titled "CIA Director John Brennan Pretends Foreign Cryptography Doesn't Exist." Cryptography is a decidedly international game today; note the many countries mentioned above as having developed various algorithms, not the least of which is the fact that NIST's Advanced Encryption Standard employs an algorithm submitted by cryptographers from Belgium. For more evidence, see Schneier's Worldwide Encryption Products Survey (February 2016).


On a related topic, public key crypto schemes can be used for several purposes, including key exchange, digital signatures, authentication, and more. In those PKC systems used for SKC key exchange, the PKC key lengths are chosen so as to be resistant to some selected level of attack. The length of the secret keys exchanged via that system have to have at least the same level of attack resistance. Thus, the three parameters of such a system — system strength, secret key strength, and public key strength — must be matched. This topic is explored in more detail in Determining Strengths For Public Keys Used For Exchanging Symmetric Keys (RFC 3766).

4. TRUST MODELS

Secure use of cryptography requires trust. While secret key cryptography can ensure message confidentiality and hash codes can ensure integrity, none of this works without trust. In SKC, Alice and Bob had to share a secret key. PKC solved the secret distribution problem, but how does Alice really know that Bob is who he says he is? Just because Bob has a public and private key, and purports to be "Bob," how does Alice know that a malicious person (Mallory) is not pretending to be Bob?

There are a number of trust models employed by various cryptographic schemes. This section will explore three of them:

  • The web of trust employed by Pretty Good Privacy (PGP) users, who hold their own set of trusted public keys.
  • Kerberos, a secret key distribution scheme using a trusted third party.
  • Certificates, which allow a set of trusted third parties to authenticate each other and, by implication, each other's users.

Each of these trust models differs in complexity, general applicability, scope, and scalability.

4.1. PGP Web of Trust

Pretty Good Privacy (described more below in Section 5.5) is a widely used private e-mail scheme based on public key methods. A PGP user maintains a local keyring of all their known and trusted public keys. The user makes their own determination about the trustworthiness of a key using what is called a "web of trust."

FIGURE 5: GPG keychain.

Figure 5 shows a PGP-formatted keychain from the GNU Privacy Guard (GPG) software, an implementation of the OpenPGP standard. This is a section of my keychain, so only includes public keys from individuals whom I know and, presumably, trust. Note that keys are associated with e-mail addresses rather than individual names.

In general, the PGP Web of trust works as follows. Suppose that Alice needs Bob's public key. Alice could just ask Bob for it directly via e-mail or download the public key from a PGP key server; this server might a well-known PGP key repository or a site that Bob maintains himself. In fact, Bob's public key might be stored or listed in many places. (My public key, for example, can be found at https://www.garykessler.net/pubkey.html or at several public PGP key servers, including https://keys.openpgp.org.) Alice is prepared to believe that Bob's public key, as stored at these locations, is valid.

Suppose Carol claims to hold Bob's public key and offers to give the key to Alice. How does Alice know that Carol's version of Bob's key is valid or if Carol is actually giving Alice a key that will allow Mallory access to messages? The answer is, "It depends." If Alice trusts Carol and Carol says that she thinks that her version of Bob's key is valid, then Alice may — at her option — trust that key. And trust is not necessarily transitive; if Dave has a copy of Bob's key and Carol trusts Dave, it does not necessarily follow that Alice trusts Dave even if she does trust Carol.

The point here is that who Alice trusts and how she makes that determination is strictly up to Alice. PGP makes no statement and has no protocol about how one user determines whether they trust another user or not. In any case, encryption and signatures based on public keys can only be used when the appropriate public key is on the user's keyring.

4.2. Kerberos

Kerberos is a commonly used authentication scheme on the Internet. Developed by MIT's Project Athena, Kerberos is named for the three-headed dog who, according to Greek mythology, guards the entrance of Hades (rather than the exit, for some reason!).

Kerberos employs a client/server architecture and provides user-to-server authentication rather than host-to-host authentication. In this model, security and authentication will be based on secret key technology where every host on the network has its own secret key. It would clearly be unmanageable if every host had to know the keys of all other hosts so a secure, trusted host somewhere on the network, known as a Key Distribution Center (KDC), knows the keys for all of the hosts (or at least some of the hosts within a portion of the network, called a realm). In this way, when a new node is brought online, only the KDC and the new node need to be configured with the node's key; keys can be distributed physically or by some other secure means.

FIGURE 6: Kerberos architecture.


The Kerberos Server/KDC has two main functions (Figure 6), known as the Authentication Server (AS) and Ticket-Granting Server (TGS). The steps in establishing an authenticated session between an application client and the application server are:
  1. The Kerberos client software establishes a connection with the Kerberos server's AS function. The AS first authenticates that the client is who it purports to be. The AS then provides the client with a secret key for this login session (the TGS session key) and a ticket-granting ticket (TGT), which gives the client permission to talk to the TGS. The ticket has a finite lifetime so that the authentication process is repeated periodically.
  2. The client now communicates with the TGS to obtain the Application Server's key so that it (the client) can establish a connection to the service it wants. The client supplies the TGS with the TGS session key and TGT; the TGS responds with an application session key (ASK) and an encrypted form of the Application Server's secret key; this secret key is never sent on the network in any other form.
  3. The client has now authenticated itself and can prove its identity to the Application Server by supplying the Kerberos ticket, application session key, and encrypted Application Server secret key. The Application Server responds with similarly encrypted information to authenticate itself to the client. At this point, the client can initiate the intended service requests (e.g., Telnet, FTP, HTTP, or e-commerce transaction session establishment).

The current version of this protocol is Kerberos V5 (described in RFC 1510). While the details of their operation, functional capabilities, and message formats are different, the conceptual overview above pretty much holds for both. One primary difference is that Kerberos V4 uses only DES to generate keys and encrypt messages, while V5 allows other schemes to be employed (although DES is still the most widely algorithm used).

4.3. Public Key Certificates and Certificate Authorities

Certificates and Certificate Authorities (CA) are necessary for widespread use of cryptography for e-commerce applications. While a combination of secret and public key cryptography can solve the business issues discussed above, crypto cannot alone address the trust issues that must exist between a customer and vendor in the very fluid, very dynamic e-commerce relationship. How, for example, does one site obtain another party's public key? How does a recipient determine if a public key really belongs to the sender? How does the recipient know that the sender is using their public key for a legitimate purpose for which they are authorized? When does a public key expire? How can a key be revoked in case of compromise or loss?

The basic concept of a certificate is one that is familiar to all of us. A driver's license, credit card, or SCUBA certification, for example, identify us to others, indicate something that we are authorized to do, have an expiration date, and identify the authority that granted the certificate.

As complicated as this may sound, it really isn't. Consider driver's licenses. I have one issued by the State of Florida. The license establishes my identity, indicates the type of vehicles that I can operate and the fact that I must wear corrective lenses while doing so, identifies the issuing authority, and notes that I am an organ donor. When I drive in other states, the other jurisdictions throughout the U.S. recognize the authority of Florida to issue this "certificate" and they trust the information it contains. When I leave the U.S., everything changes. When I am in Aruba, Australia, Canada, Israel, and many other countries, they will accept not the Florida license, per se, but any license issued in the U.S. This analogy represents the certificate trust chain, where even certificates carry certificates.

For purposes of electronic transactions, certificates are digital documents. The specific functions of the certificate include:

  • Establish identity: Associate, or bind, a public key to an individual, organization, corporate position, or other entity.
  • Assign authority: Establish what actions the holder may or may not take based upon this certificate.
  • Secure confidential information (e.g., encrypting the session's symmetric key for data confidentiality).

Typically, a certificate contains a public key, a name, an expiration date, the name of the authority that issued the certificate (and, therefore, is vouching for the identity of the user), a serial number, any pertinent policies describing how the certificate was issued and/or how the certificate may be used, the digital signature of the certificate issuer, and perhaps other information.

FIGURE 7: VeriSign Class 3 certificate.

A sample abbreviated certificate is shown in Figure 7. This is a typical certificate found in a browser, in this case, Mozilla Firefox (MacOS). While this is a certificate issued by VeriSign, many root-level certificates can be found shipped with browsers. When the browser makes a connection to a secure Web site, the Web server sends its public key certificate to the browser. The browser then checks the certificate's signature against the public key that it has stored; if there is a match, the certificate is taken as valid and the Web site verified by this certificate is considered to be "trusted."

The most widely accepted certificate format is the one defined in International Telecommunication Union Telecommunication Standardization Sector (ITU-T) Recommendation X.509. Rec. X.509 is a specification used around the world and any applications complying with X.509 can share certificates. Most certificates today comply with X.509 Version 3 and contain the following information:

  • Version number
  • Certificate serial number
  • Signature algorithm identifier
  • Issuer's name and unique identifier
  • Validity (or operational) period
  • Subject's name and unique identifier
  • Subject public key information
  • Standard extensions
    • Certificate appropriate use definition
    • Key usage limitation definition
    • Certificate policy information
  • Other extensions
    • Application-specific
    • CA-specific

Certificate authorities are the repositories for public keys and can be any agency that issues certificates. A company, for example, may issue certificates to its employees, a college/university to its students, a store to its customers, an Internet service provider to its users, or a government to its constituents.

When a sender needs an intended receiver's public key, the sender must get that key from the receiver's CA. That scheme is straight-forward if the sender and receiver have certificates issued by the same CA. If not, how does the sender know to trust the foreign CA? One industry wag has noted, about trust: "You are either born with it or have it granted upon you." Thus, some CAs will be trusted because they are known to be reputable, such as the CAs operated by AT&T Services, Comodo, DigiCert (formerly GTE Cybertrust), EnTrust, Broadcom (formerly Symantec, formerly VeriSign), and Thawte. CAs, in turn, form trust relationships with other CAs. Thus, if a user queries a foreign CA for information, the user may ask to see a list of CAs that establish a "chain of trust" back to the user.

One major feature to look for in a CA is their identification policies and procedures. When a user generates a key pair and forwards the public key to a CA, the CA has to check the sender's identification and takes any steps necessary to assure itself that the request is really coming from the advertised sender. Different CAs have different identification policies and will, therefore, be trusted differently by other CAs. Verification of identity is just one of many issues that are part of a CA's Certification Practice Statement (CPS) and policies; other issues include how the CA protects the public keys in its care, how lost or compromised keys are revoked, and how the CA protects its own private keys.

As a final note, CAs are not immune to attack and certificates themselves are able to be counterfeited. One of the first such episodes occurred at the turn of the century; on January 29 and 30, 2001, two VeriSign Class 3 code-signing digital certificates were issued to an individual who fraudulently claimed to be a Microsoft employee (CERT/CC CA-2001-04 and Microsoft Security Bulletin MS01-017 - Critical). Problems have continued over the years; good write-ups on this can be found at "Another Certification Authority Breached (the 12th!)" and "How Cybercrime Exploits Digital Certificates." Readers are also urged to read "Certification Authorities Under Attack: A Plea for Certificate Legitimation" (Oppliger, R., January/February 2014, IEEE Internet Computing, 18(1), 40-47).

As a partial way to address this issue, the Internet Security Research Group (ISRG) designed the Automated Certificate Management Environment (ACME) protocol. ACME is a communications protocol that streamlines the process of deploying a Public Key Infrastructure (PKI) by automating interactions between CAs and Web servers that wish to obtain a certificate. More information can be found at the Let's Encrypt Web site, an ACME-based CA service provided by the ISRG.

4.4. Summary

The paragraphs above describe three very different trust models. It is hard to say that any one is better than the others; it depends upon your application. One of the biggest and fastest growing applications of cryptography today, though, is electronic commerce (e-commerce), a term that itself begs for a formal definition.

PGP's web of trust is easy to maintain and very much based on the reality of users as people. The model, however, is limited; just how many public keys can a single user reliably store and maintain? And what if you are using the "wrong" computer when you want to send a message and can't access your keyring? How easy it is to revoke a key if it is compromised? PGP may also not scale well to an e-commerce scenario of secure communication between total strangers on short-notice.

Kerberos overcomes many of the problems of PGP's web of trust, in that it is scalable and its scope can be very large. However, it also requires that the Kerberos server have a priori knowledge of all client systems prior to any transactions, which makes it unfeasible for "hit-and-run" client/server relationships as seen in e-commerce.

Certificates and the collection of CAs will form a PKI. In the early days of the Internet, every host had to maintain a list of every other host; the Domain Name System (DNS) introduced the idea of a distributed database for this purpose and the DNS is one of the key reasons that the Internet has grown as it has. A PKI will fill a similar void in the e-commerce and PKC realm.

While certificates and the benefits of a PKI are most often associated with electronic commerce, the applications for PKI are much broader and include secure electronic mail, payments and electronic checks, Electronic Data Interchange (EDI), secure transfer of Domain Name System (DNS) and routing information, electronic forms, and digitally signed documents. A single "global PKI" is still many years away, that is the ultimate goal of today's work as international electronic commerce changes the way in which we do business in a similar way in which the Internet has changed the way in which we communicate.

5. CRYPTOGRAPHIC ALGORITHMS IN ACTION

The paragraphs above have provided an overview of the different types of cryptographic algorithms, as well as some examples of some available protocols and schemes. Table 3 provides a list of some other noteworthy schemes and cryptosystems employed — or proposed — for a variety of functions, most notably electronic commerce and secure communication. The paragraphs below will show several real cryptographic applications that many of us employ (knowingly or not) everyday for password protection and private communication. Some of the schemes described below never were widely deployed but are still historically interesting, thus remain included here. This list is, by no means, exhaustive but describes items that are of significant current and/or historic importance (a subjective judgement, to be sure).

BitmessageA decentralized, encrypted, peer-to-peer, trustless communications protocol for message exchange. The decentralized design, outlined in "Bitmessage: A Peer-to-Peer Message Authentication and Delivery System" (Warren, 2012), is conceptually based on the Bitcoin model.
CapstoneA now-defunct U.S. National Institute of Standards and Technology (NIST) and National Security Agency (NSA) project under the Bush Sr. and Clinton administrations for publicly available strong cryptography with keys escrowed by the government (NIST and the Treasury Dept.). Capstone included one or more tamper-proof computer chips for implementation (Clipper), a secret key encryption algorithm (Skipjack), digital signature algorithm (DSA), key exchange algorithm (KEA), and hash algorithm (SHA).
Challenge-Handshake Authentication Protocol (CHAP)An authentication scheme that allows one party to prove who they are to a second party by demonstrating knowledge of a shared secret without actually divulging that shared secret to a third party who might be listening. Described in RFC 1994.
Chips-Message Robust Authentication (CHIMERA)A scheme proposed for authenticating navigation data and the spreading code of civilian signals in the Global Positioning System (GPS). This is an anti-spoofing mechanism to protect the unencrypted civilian signals; GPS military signals are encrypted.
ClipperThe computer chip that would implement the Skipjack encryption scheme. The Clipper chip was to have had a deliberate backdoor so that material encrypted with this device would not be beyond the government's reach. Described in 1993, Clipper was dead by 1996. See also EPIC's The Clipper Chip Web page.
Cryptography Research and Evaluation Committees (CRYPTEC)Similar in concept to the NIST AES process and NESSIE, CRYPTEC is the Japanese government's process to evaluate algorithms submitted for government and industry applications. CRYPTEX maintains a list of public key and secret key ciphers, hash functions, MACs, and other crypto algorithms approved for various applications in government environments.
Derived Unique Key Per Transaction (DUKPT)A key management scheme used for debit and credit card verification with point-of-sale (POS) transaction systems, automated teller machines (ATMs), and other financial applications. In DUKPT, a unique key is derived for each transaction based upon a fixed, shared key in such a way that knowledge of one derived key does not easily yield knowledge of other keys (including the fixed key). Therefore, if one of the derived keys is compromised, neither past nor subsequent transactions are endangered. DUKPT is specified in American National Standard (ANS) ANSI X9.24-1:2009 (Retail Financial Services Symmetric Key Management Part 1: Using Symmetric Techniques) and can be purchased at the ANSI X9.24 Web page.
ECRYPT Stream Cipher Project (eSTREAM)The eSTREAM project came about as a result of the failure of the NESSIE project to produce a stream cipher that survived cryptanalysis. eSTREAM ran from 2004 to 2008 with the primary purpose of promoting the design of efficient and compact stream ciphers. As of September 2008, the eSTREAM suite contains seven sciphers.
Escrowed Encryption Standard (EES)Largely unused, a controversial crypto scheme employing the SKIPJACK secret key crypto algorithm and a Law Enforcement Access Field (LEAF) creation method. LEAF was one part of the key escrow system and allowed for decryption of ciphertext messages that had been intercepted by law enforcement agencies. Described more in FIPS PUB 185 (archived; no longer in force).
Federal Information Processing Standards (FIPS)These computer security- and crypto-related FIPS PUBs are produced by the U.S. National Institute of Standards and Technology (NIST) as standards for the U.S. Government. Current Federal Information Processing Standards (FIPS) related to crytography include:
FortezzaA PCMCIA card developed by NSA that implements the Capstone algorithms, intended for use with the Defense Messaging Service (DMS). Originally called Tessera.
GOSTGOST is a family of algorithms defined in the Russian cryptographic standards. Although most of the specifications are written in Russian, a series of RFCs describe some of the aspects so that the algorithms can be used effectively in Internet applications:
  • RFC 4357: Additional Cryptographic Algorithms for Use with GOST 28147-89, GOST R 34.10-94, GOST R 34.10-2001, and GOST R 34.11-94 Algorithms
  • RFC 4490: Using the GOST 28147-89, GOST R 34.11-94, GOST R 34.10-94, and GOST R 34.10-2001 Algorithms with Cryptographic Message Syntax (CMS)
  • RFC 4491: Using the GOST R 34.10-94, GOST R 34.10-2001, and GOST R 34.11-94 Algorithms with the Internet X.509 Public Key Infrastructure Certificate and CRL Profile
  • RFC 5830: GOST 28147-89: Encryption, Decryption, and Message Authentication Code (MAC) Algorithms
  • RFC 6986: GOST R 34.11-2012: Hash Function Algorithm
  • RFC 7091: GOST R 34.10-2012: Digital Signature Algorithm (Updates RFC 5832: GOST R 34.10-2001)
  • RFC 7801: GOST R 34.12-2015: Block Cipher "Kuznyechik"
  • RFC 7836: Guidelines on the Cryptographic Algorithms to Accompany the Usage of Standards GOST R 34.10-2012 and GOST R 34.11-2012
  • RFC 8891: GOST R 34.12-2015: Block Cipher "Magma"
IP Security (IPsec)The IPsec protocol suite is used to provide privacy and authentication services at the IP layer. An overview of the protocol suite and of the documents comprising IPsec can be found in RFC 2411. Other documents include:
  • RFC 4301: IP security architecture.
  • RFC 4302: IP Authentication Header (AH), one of the two primary IPsec functions; AH provides connectionless integrity and data origin authentication for IP datagrams and protects against replay attacks.
  • RFC 4303: IP Encapsulating Security Payload (ESP), the other primary IPsec function; ESP provides a variety of security services within IPsec.
  • RFC 4304: Extended Sequence Number (ESN) Addendum, allows for negotiation of a 32- or 64- bit sequence number, used to detect replay attacks.
  • RFC 4305: Cryptographic algorithm implementation requirements for ESP and AH.
  • RFC 5996: The Internet Key Exchange (IKE) protocol, version 2, providing for mutual authentication and establishing and maintaining security associations.
    • IKE v1 was described in three separate documents, RFC 2407 (application of ISAKMP to IPsec), RFC 2408 (ISAKMP, a framework for key management and security associations), and RFC 2409 (IKE, using part of Oakley and part of SKEME in conjunction with ISAKMP to obtain authenticated keying material for use with ISAKMP, and for other security associations such as AH and ESP). IKE v1 is obsoleted with the introduction of IKEv2.
  • RFC 4307: Cryptographic algorithms used with IKEv2.
  • RFC 4308: Crypto suites for IPsec, IKE, and IKEv2.
  • RFC 4309: The use of AES in CBC-MAC mode with IPsec ESP.
  • RFC 4312: The use of the Camellia cipher algorithm in IPsec.
  • RFC 4359: The Use of RSA/SHA-1 Signatures within Encapsulating Security Payload (ESP) and Authentication Header (AH).
  • RFC 4434: Describes AES-XCBC-PRF-128, a pseudo-random function derived from the AES for use with IKE.
  • RFC 2403: Describes use of the HMAC with MD5 algorithm for data origin authentication and integrity protection in both AH and ESP.
  • RFC 2405: Describes use of DES-CBC (DES in Cipher Block Chaining Mode) for confidentiality in ESP.
  • RFC 2410: Defines use of the NULL encryption algorithm (i.e., provides authentication and integrity without confidentiality) in ESP.
  • RFC 2412: Describes OAKLEY, a key determination and distribution protocol.
  • RFC 2451: Describes use of Cipher Block Chaining (CBC) mode cipher algorithms with ESP.
  • RFCs 2522 and 2523: Description of Photuris, a session-key management protocol for IPsec.

In addition, RFC 6379 describes Suite B Cryptographic Suites for IPsec and RFC 6380 describes the Suite B profile for IPsec.

IPsec was first proposed for use with IP version 6 (IPv6), but can also be employed with the current IP version, IPv4.

(See more detail about IPsec below in Section 5.6.)

Internet Security Association and Key Management Protocol (ISAKMP/OAKLEY)ISAKMP/OAKLEY provide an infrastructure for Internet secure communications. ISAKMP, designed by the National Security Agency (NSA) and described in RFC 2408, is a framework for key management and security associations, independent of the key generation and cryptographic algorithms actually employed. The OAKLEY Key Determination Protocol, described in RFC 2412, is a key determination and distribution protocol using a variation of Diffie-Hellman.
KerberosA secret key encryption and authentication system, designed to authenticate requests for network resources within a user domain rather than to authenticate messages. Kerberos also uses a trusted third-party approach; a client communications with the Kerberos server to obtain "credentials" so that it may access services at the application server. Kerberos V4 used DES to generate keys and encrypt messages; Kerberos V5 uses DES and other schemes for key generation.

Microsoft added support for Kerberos V5 — with some proprietary extensions — in Windows 2000 Active Directory. There are many Kerberos articles posted at Microsoft's Knowledge Base, notably "Kerberos Explained."
Keyed-Hash Message Authentication Code (HMAC)A message authentication scheme based upon secret key cryptography and the secret key shared between two parties rather than public key methods. Described in FIPS PUB 198 and RFC 2104. (See Section 5.19 below for details on HMAC operation.)
Message Digest Cipher (MDC)Invented by Peter Gutman, MDC turns a one-way hash function into a block cipher.
MIME Object Security Services (MOSS)Designed as a successor to PEM to provide PEM-based security services to MIME messages. Described in RFC 1848. Never widely implemented and now defunct.
Mujahedeen SecretsA Windows GUI, PGP-like cryptosystem. Developed by supporters of Al-Qaeda, the program employs the five finalist AES algorithms, namely, MARS, RC6, Rijndael, Serpent, and Twofish. Also described in Inspire Magazine, Issue 1, pp. 41-44 and Inspire Magazine, Issue 2, pp. 58-59. Additional related information can also be found in "How Al-Qaeda Uses Encryption Post-Snowden (Part 2)."
New European Schemes for Signatures, Integrity and Encryption (NESSIE)NESSIE was an independent project meant to augment the work of NIST during the AES adoption process by putting out an open call for new cryptographic primitives. The NESSIE project ran from about 2000-2003. While several new block ciper, PKC, MAC, and digital signature algorithms were found during the NESSIE process, no new stream cipher survived cryptanalysis. As a result, the ECRYPT Stream Cipher Project (eSTREAM) was created.
NSA Suite B CryptographyAn NSA standard for securing information at the SECRET level. Defines use of:
  • Advanced Encryption Standard (AES) with key sizes of 128 and 256 bits, per FIPS PUB 197 for encryption
  • The Ephemeral Unified Model and the One-Pass Diffie Hellman (referred to as ECDH) using the curves with 256 and 384-bit prime moduli, per NIST Special Publication 800-56A for key exchange
  • Elliptic Curve Digital Signature Algorithm (ECDSA) using the curves with 256 and 384-bit prime moduli, per FIPS PUB 186-3 for digital signatures
  • Secure Hash Algorithm (SHA) using 256 and 384 bits, per FIPS PUB 180-3 for hashing

RFC 6239 describes Suite B Cryptographic Suites for Secure Shell (SSH) and RFC 6379 describes Suite B Cryptographic Suites for Secure IP (IPsec).

RFC 8423 reclassifies the RFCs related to the Suite B cryptographic algorithms as Historic, and it discusses the reasons for doing so.

Pretty Good Privacy (PGP)A family of cryptographic routines for e-mail, file, and disk encryption developed by Philip Zimmermann. PGP 2.6.x uses RSA for key management and digital signatures, IDEA for message encryption, and MD5 for computing the message's hash value; more information can also be found in RFC 1991. PGP 5.x (formerly known as "PGP 3") uses Diffie-Hellman/DSS for key management and digital signatures; IDEA, CAST, or 3DES for message encryption; and MD5 or SHA for computing the message's hash value. OpenPGP, described in RFC 2440, is an open definition of security software based on PGP 5.x. The GNU Privacy Guard (GPG) is a free software version of OpenPGP.

(See more detail about PGP below in Section 5.5.)

Privacy Enhanced Mail (PEM)An IETF standard for secure electronic mail over the Internet, including provisions for encryption (DES), authentication, and key management (DES, RSA). Developed by the IETF but never widely used. Described in the following RFCs:
  • RFC 1421: Part I, Message Encryption and Authentication Procedures
  • RFC 1422: Part II, Certificate-Based Key Management
  • RFC 1423: Part III, Algorithms, Modes, and Identifiers
  • RFC 1424: Part IV, Key Certification and Related Services
Private Communication Technology (PCT)Developed by Microsoft for secure communication on the Internet. PCT supported Diffie-Hellman, Fortezza, and RSA for key establishment; DES, RC2, RC4, and triple-DES for encryption; and DSA and RSA message signatures. Never widely used; superceded by SSL and TLS.
Secure Electronic Transaction (SET)A communications protocol for securing credit card transactions, developed by MasterCard and VISA, in cooperation with IBM, Microsoft, RSA, and other companies. Merged two other protocols: Secure Electronic Payment Protocol (SEPP), an open specification for secure bank card transactions over the Internet developed by CyberCash, GTE, IBM, MasterCard, and Netscape; and Secure Transaction Technology (STT), a secure payment protocol developed by Microsoft and Visa International. Supports DES and RC4 for encryption, and RSA for signatures, key exchange, and public key encryption of bank card numbers. SET V1.0 is described in Book 1, Book 2, and Book 3. SET has been superceded by SSL and TLS.
Secure Hypertext Transfer Protocol (S-HTTP)An extension to HTTP to provide secure exchange of documents over the World Wide Web. Supported algorithms include RSA and Kerberos for key exchange, DES, IDEA, RC2, and Triple-DES for encryption. Described in RFC 2660. S-HTTP was never as widely used as HTTP over SSL (https).
Secure Multipurpose Internet Mail Extensions (S/MIME)An IETF secure e-mail scheme superceding PEM, and adding digital signature and encryption capability to Internet MIME messages. S/MIME Version 3.1 is described in RFCs 3850 and 3851, and employs the Cryptographic Message Syntax described in RFCs 3369 and 3370.

(More detail about S/MIME can be found below in Section 5.15.)
Secure Sockets Layer (SSL)Developed in 1995 by Netscape Communications to provide application-independent security and privacy over the Internet. SSL is designed so that protocols such as HTTP, FTP (File Transfer Protocol), and Telnet can operate over it transparently. SSL allows both server authentication (mandatory) and client authentication (optional). RSA is used during negotiation to exchange keys and identify the actual cryptographic algorithm (DES, IDEA, RC2, RC4, or 3DES) to use for the session. SSL also uses MD5 for message digests and X.509 public key certificates. SSL was found to be breakable soon after the IETF announced formation of group to work on TLS and RFC 6176 specifically prohibits the use of SSL v2.0 by TLS clients. SSL version 3.0 is described in RFC 6101. All versions of SSL are now deprecated in favor of TLS; TLS v1.0 is sometimes referred to as "SSL v3.1."

(More detail about SSL can be found below in Section 5.7.)
Server Gated Cryptography (SGC)Microsoft extension to SSL that provided strong encryption for online banking and other financial applications using RC2 (128-bit key), RC4 (128-bit key), DES (56-bit key), or 3DES (equivalent of 168-bit key). Use of SGC required an Windows NT Server running Internet Information Server (IIS) 4.0 with a valid SGC certificate. SGC was available in 32-bit Windows versions of Internet Explorer (IE) 4.0; support for Mac, Unix, and 16-bit Windows versions of IE was planned, but never materialized, and SGC was made moot when browsers started to ship with 128-bit encryption.
ShangMi (SM) Cipher SuitesA suite of authentication, encryption, and hash algorithms from the People's Republic of China.
  • SM2 Cryptography Algorithm: A public key crypto scheme based on elliptic curves. An overview of the specification, in Chinese, can be found in GM/T 0009-2012. Additional specifications can be found in:
  • SM3 Cryptographic Hash Algorithm: A hash algorithm operating on 512-bit blocks to produce a 256-bit hash value. Described in GB/T 32905-2016.
  • SM4 Block Cipher Algorithm: A Feistel block cipher algorithm with a block length and key length of 128 bits, and 32 rounds. Described in GB/T 32907-2016.
An application of the ShangMi Cipher Suites in TLS can be found in RFC 8998.
Signal ProtocolA protocol for providing end-to-end encryption for voice calls, video calls, and instant messaging (including group chats). Employing a combination of AES, ECC, and HMAC algorithms, it offers such features as confidentiality, integrity, authentication, forward/future secrecy, and message repudiation. Signal is particularly interesting because of its lineage and widespread use. The Signal Protocol's earliest versions were known as TextSecure, first developed by Open Whisper Systems in 2013. TextSecure itself was based on a 2004 protocol called Off-the-Record (OTR) Messaging, designed as an improvement over OpenPGP and S/MIME. TextSecure v2 (2014) introduced a scheme called the Axolotl Ratchet for key exchange and added additional communication features. After subsequent iterations improving key management (and the renaming of the key exchange protocol to Double Ratchet), additional cryptographic primitives, and the addition of an encrypted voice calling application (RedPhone), TextSecure was renamed Signal Protocol in 2016. The Ratchet key exchange algorithm is at the heart of the power of this system. Most messaging apps employ the users' public and private keys; the weakness here is that if the phone falls into someone else's hands, all of the messages on the device — including deleted messages — can be decrypted. The Ratchet algorithm generates a set of so-called "temporary keys" for each user, based upon that user's public/private key pair. When two users exchange messages, the Signal protocol creates a secret key by combining the temporary and permanent pairs of public and private keys for both users. Each message is assigned its own secret key. Because the generation of the secret key requires access to both users' private keys, it exists only on their two devices. The Signal Protocol is/has been employed in:
  • WhatsApp (introduced 2014)
  • G Data Software's Secure Chat (introduced 2015; service discontinued 2018)
  • Google's Allo app (introduced 2016; discontinued in favor of Messages app, 2019)
  • Facebook Messenger (introduced 2016)
  • Skype's Private Conversations mode (introduced 2018)
  • All of Google's Rich Communication Services (RCS) on Android systems (introduced 2020)
A reasonably good writeup of the protocol can be found in "Demystifying the Signal Protocol for End-to-End Encryption (E2EE)" by Kozhukhovskaya, Mora, and Wong (2017).
Simple Authentication and Security Layer (SASL)A framework for providing authentication and data security services in connection-oriented protocols (a la TCP), described in RFC 4422. It provides a structured interface and allows new protocols to reuse existing authentication mechanisms and allows old protocols to make use of new mechanisms.

It has been common practice on the Internet to permit anonymous access to various services, employing a plain-text password using a user name of "anonymous" and a password of an email address or some other identifying information. New IETF protocols disallow plain-text logins. The Anonymous SASL Mechanism (RFC 4505) provides a method for anonymous logins within the SASL framework.
Simple Key-Management for Internet Protocol (SKIP)Key management scheme for secure IP communication, specifically for IPsec, and designed by Aziz and Diffie. SKIP essentially defines a public key infrastructure for the Internet and even uses X.509 certificates. Most public key cryptosystems assign keys on a per-session basis, which is inconvenient for the Internet since IP is connectionless. Instead, SKIP provides a basis for secure communication between any pair of Internet hosts. SKIP can employ DES, 3DES, IDEA, RC2, RC5, MD5, and SHA-1. As it happened, SKIP was not adopted for IPsec; IKE was selected instead.
SM9Chinese Standard GM/T0044-2016 SM9 (2016) is the Chinese national standard for Identity Based Cryptography. SM9 comprises three cryptographic algorithms, namely the Identity Based Digital Signature Algorithm, Identity Based Key Agreement Algorithm, and Identity Based Key Encapsulation Algorithm (allowing one party to securely send a symmetric key to another party). The SM9 scheme is also described in The SM9 Cryptographic Schemes (Z. Cheng).
TelegramTelegram, launched in 2013, is a cloud-based instant messaging and voice over IP (VoIP) service, with client app software available for all major computer and mobile device operating systems. Telegram allows users to exchange messages, photos, videos, etc., and supplies end-to-end encryption using a protocol called MTProto. stickers, audio and files of any type. MTProto employs 256-bit AES, 2048-bit RSA, and Diffie-Hellman key exchange. There have been several contriversies with Telegram, not the least of which has to do with the nationality of the founders and the true location of the business, as well as some operation issues. From a cryptological viewpoint, however, one cautionary tale can be found in "On the CCA (in)security of MTProto" (Jakobsen & Orlandi, 2015), who describe some of the crypto weaknesses of the protocol; specifically, that "MTProto does not satisfy the definitions of authenticated encryption (AE) or indistinguishability under chosen-ciphertext attack (IND-CCA)" (p. 1).
Transmission Control Protocol (TCP) encryption (tcpcrypt)As of 2019, the majority of Internet TCP traffic is not encrypted. The two primary reasons for this are (1) many legacy protocols have no mechanism with which to employ encryption (e.g., without a command such as STARTSSL, the protocol cannot invoke use of any encryption) and (2) many legacy applications cannot be upgraded, so no new encryption can be added. The response from the IETF's TCP Increased Security Working Group was to define a transparent way within the transport layer (i.e., TCP) with which to invoke encryption. The TCP Encryption Negotiation Option (TCP-ENO) addresses these two problems with an out-of-band, fully backward-compatible TCP option with which to negotiate use of encryption. TCP-ENO is described in RFC 8547 and tcpcrypt, an encryption protocol to protect TCP streams, is described in RFC 8548.
Transport Layer Security (TLS)TLS v1.0 is an IETF specification (RFC 2246) intended to replace SSL v3.0. TLS v1.0 employs Triple-DES (secret key cryptography), SHA (hash), Diffie-Hellman (key exchange), and DSS (digital signatures). TLS v1.0 was vulnerable to attack and updated by v1.1 (RFC 4346), which is now classified as an HISTORIC specification. TLS v1.1 was replaced by TLS v1.2 (RFC 5246) and, subsequently, by v1.3 (RFC 8446).

TLS is designed to operate over TCP. The IETF developed the Datagram Transport Layer Security (DTLS) protocol to operate over UDP. DTLS v1.2 is described in RFC 6347.

(See more detail about TLS below in Section 5.7.)
TrueCryptOpen source, multi-platform cryptography software that can be used to encrypt a file, partition, or entire disk. One of TrueCrypt's more interesting features is that of plausible deniability with hidden volumes or hidden operating systems. The original Web site, truecrypt.org, suddenly went dark in May 2014. The current fork of TrueCrypt is VeraCrypt.

(See more detail about TrueCrypt below in Section 5.11.)
X.509ITU-T recommendation for the format of certificates for the public key infrastructure. Certificates map (bind) a user identity to a public key. The IETF application of X.509 certificates is documented in RFC 5280. An Internet X.509 Public Key Infrastructure is further defined in RFC 4210 (Certificate Management Protocols) and RFC 3647 (Certificate Policy and Certification Practices Framework).

5.1. Password Protection

Nearly all modern multiuser computer and network operating systems employ passwords at the very least to protect and authenticate users accessing computer and/or network resources. But passwords are not typically kept on a host or server in plaintext, but are generally encrypted using some sort of hash scheme.

A) /etc/passwd file root:Jbw6BwE4XoUHo:0:0:root:/root:/bin/bash carol:FM5ikbQt1K052:502:100:Carol Monaghan:/home/carol:/bin/bash alex:LqAi7Mdyg/HcQ:503:100:Alex Insley:/home/alex:/bin/bash gary:FkJXupRyFqY4s:501:100:Gary Kessler:/home/gary:/bin/bash todd:edGqQUAaGv7g6:506:101:Todd Pritsky:/home/todd:/bin/bash josh:FiH0ONcjPut1g:505:101:Joshua Kessler:/home/webroot:/bin/bash B.1) /etc/passwd file (with shadow passwords) root:x:0:0:root:/root:/bin/bash carol:x:502:100:Carol Monaghan:/home/carol:/bin/bash alex:x:503:100:Alex Insley:/home/alex:/bin/bash gary:x:501:100:Gary Kessler:/home/gary:/bin/bash todd:x:506:101:Todd Pritsky:/home/todd:/bin/bash josh:x:505:101:Joshua Kessler:/home/webroot:/bin/bash B.2) /etc/shadow file root:AGFw$1$P4u/uhLK$l2.HP35rlu65WlfCzq:11449:0:99999:7::: carol:kjHaN%35a8xMM8a/0kMl1?fwtLAM.K&kw.:11449:0:99999:7::: alex:1$1KKmfTy0a7#3.LL9a8H71lkwn/.hH22a:11449:0:99999:7::: gary:9ajlknknKJHjhnu7298ypnAIJKL$Jh.hnk:11449:0:99999:7::: todd:798POJ90uab6.k$klPqMt%alMlprWqu6$.:11492:0:99999:7::: josh:Awmqpsui*787pjnsnJJK%aappaMpQo07.8:11492:0:99999:7:::

FIGURE 8: Sample entries in Unix/Linux password files.

Unix/Linux, for example, uses a well-known hash via its crypt() function. Passwords are stored in the /etc/passwd file (Figure 8A); each record in the file contains the username, hashed password, user's individual and group numbers, user's name, home directory, and shell program; these fields are separated by colons (:). Note that each password is stored as a 13-byte string. The first two characters are actually a salt, randomness added to each password so that if two users have the same password, they will still be encrypted differently; the salt, in fact, provides a means so that a single password might have 4096 different encryptions. The remaining 11 bytes are the password hash, calculated using DES.

As it happens, the /etc/passwd file is world-readable on Unix systems. This fact, coupled with the weak encryption of the passwords, resulted in the development of the shadow password system where passwords are kept in a separate, non-world-readable file used in conjunction with the normal password file. When shadow passwords are used, the password entry in /etc/passwd is replaced with a "*" or "x" (Figure 8B.1) and the MD5 hash of the passwords are stored in /etc/shadow along with some other account information (Figure 8B.2).

Windows NT uses a similar scheme to store passwords in the Security Access Manager (SAM) file. In the NT case, all passwords are hashed using the MD4 algorithm, resulting in a 128-bit (16-byte) hash value (they are then obscured using an undocumented mathematical transformation that was a secret until distributed on the Internet). The password password, for example, might be stored as the hash value (in hexadecimal) 60771b22d73c34bd4a290a79c8b09f18.

Passwords are not saved in plaintext on computer systems precisely so they cannot be easily compromised. For similar reasons, we don't want passwords sent in plaintext across a network. But for remote logon applications, how does a client system identify itself or a user to the server? One mechanism, of course, is to send the password as a hash value and that, indeed, may be done. A weakness of that approach, however, is that an intruder can grab the password off of the network and use an off-line attack (such as a dictionary attack where an attacker takes every known word and encrypts it with the network's encryption algorithm, hoping eventually to find a match with a purloined password hash). In some situations, an attacker only has to copy the hashed password value and use it later on to gain unauthorized entry without ever learning the actual password.

An even stronger authentication method uses the password to modify a shared secret between the client and server, but never allows the password in any form to go across the network. This is the basis for the Challenge Handshake Authentication Protocol (CHAP), the remote logon process used by Windows NT.

As suggested above, Windows NT passwords are stored in a security file on a server as a 16-byte hash value. In truth, Windows NT stores two hashes; a weak hash based upon the old LAN Manager (LanMan) scheme and the newer NT hash. When a user logs on to a server from a remote workstation, the user is identified by the username, sent across the network in plaintext (no worries here; it's not a secret anyway!). The server then generates a 64-bit random number and sends it to the client (also in plaintext). This number is the challenge.

Using the LanMan scheme, the client system then encrypts the challenge using DES. Recall that DES employs a 56-bit key, acts on a 64-bit block of data, and produces a 64-bit output. In this case, the 64-bit data block is the random number. The client actually uses three different DES keys to encrypt the random number, producing three different 64-bit outputs. The first key is the first seven bytes (56 bits) of the password's hash value, the second key is the next seven bytes in the password's hash, and the third key is the remaining two bytes of the password's hash concatenated with five zero-filled bytes. (So, for the example above, the three DES keys would be 60771b22d73c34, bd4a290a79c8b0, and 9f180000000000.) Each key is applied to the random number resulting in three 64-bit outputs, which comprise the response. Thus, the server's 8-byte challenge yields a 24-byte response from the client and this is all that would be seen on the network. The server, for its part, does the same calculation to ensure that the values match.

There is, however, a significant weakness to this system. Specifically, the response is generated in such a way as to effectively reduce 16-byte hash to three smaller hashes, of length seven, seven, and two, respectively. Thus, a password cracker has to break at most a 7-byte hash. One Windows NT vulnerability test program that I used in the past reported passwords that were "too short," defined as "less than 8 characters." When I asked how the program knew that passwords were too short, the software's salespeople suggested to me that the program broke the passwords to determine their length. This was, in fact, not the case at all; all the software really had to do was to look at the last eight bytes of the Windows NT LanMan hash to see that the password was seven or fewer characters.

Consider the following example, showing the LanMan hash of two different short passwords (take a close look at the last 8 bytes):

AA: 89D42A44E77140AAAAD3B435B51404EE
AAA: 1C3A2B6D939A1021AAD3B435B51404EE

Note that the NT hash provides no such clue:

AA: C5663434F963BE79C8FD99F535E7AAD8
AAA: 6B6E0FB2ED246885B98586C73B5BFB77

It is worth noting that the discussion above describes the Microsoft version of CHAP, or MS-CHAP (MS-CHAPv2 is described in RFC 2759). MS-CHAP assumes that it is working with hashed values of the password as the key to encrypting the challenge. More traditional CHAP (RFC 1994) assumes that it is starting with passwords in plaintext. The relevance of this observation is that a CHAP client, for example, cannot be authenticated by an MS-CHAP server; both client and server must use the same CHAP version.

5.2. Diffie-Hellman Key Exchange

Diffie and Hellman introduced the concept of public key cryptography. The mathematical "trick" of Diffie-Hellman key exchange is that it is relatively easy to compute exponents compared to computing discrete logarithms. Diffie-Hellman allows two parties — the ubiquitous Alice and Bob — to generate a secret key; they need to exchange some information over an unsecure communications channel to perform the calculation but an eavesdropper cannot determine the shared secret key based upon this information.

Diffie-Hellman works like this. Alice and Bob start by agreeing on a large prime number, N. They also have to choose some number G so that G<N.

There is actually another constraint on G, namely that it must be primitive with respect to N. Primitive is a definition that is a little beyond the scope of our discussion but basically G is primitive to N if the set of N-1 values of Gi mod N for i = (1,N-1) are all different. As an example, 2 is not primitive to 7 because the set of powers of 2 from 1 to 6, mod 7 (i.e., 21 mod 7, 22 mod 7, ..., 26 mod 7) = {2,4,1,2,4,1}. On the other hand, 3 is primitive to 7 because the set of powers of 3 from 1 to 6, mod 7 = {3,2,6,4,5,1}.

(The definition of primitive introduced a new term to some readers, namely mod. The phrase x mod y (and read as written!) means "take the remainder after dividing x by y." Thus, 1 mod 7 = 1, 9 mod 6 = 3, and 8 mod 8 = 0. Read more about the modulo function in the appendix.)

Anyway, either Alice or Bob selects N and G; they then tell the other party what the values are. Alice and Bob then work independently (Figure 9):

Alice...

  1. Choose a large random number, XA < N. This is Alice's private key.
  2. Compute YA = GXA mod N. This is Alice's public key.
  3. Exchange public key with Bob.
  4. Compute KA = YBXA mod N
Bob...

  1. Choose a large random number, XB < N. This is Bob's private key.
  2. Compute YB = GXB mod N. This is Bob's public key.
  3. Exchange public key with Alice.
  4. Compute KB = YAXB mod N
FIGURE 9: Diffie-Hellman key exchange model.

Note that XA and XB are kept secret while YA and YB are openly shared; these are the private and public keys, respectively. Based on their own private key and the public key learned from the other party, Alice and Bob have computed their secret keys, KA and KB, respectively, which are equal to GXAXB mod N.

Perhaps a small example will help here. Although Alice and Bob will really choose large values for N and G, I will use small values for example only; let's use N=7 and G=3, as shown in Figure 10.

Alice...

  1. Choose private key; XA = 2
  2. Compute public key; YA = 32 mod 7 = 2
  3. Exchange public key with Bob
  4. KA = YBXA mod N = 62 mod 7 = 1
Bob...

  1. Choose private key; XB = 3
  2. Compute public key; YB = 33 mod 7 = 6
  3. Exchange public key with Alice
  4. KB = YAXB mod N = 23 mod 7 = 1
FIGURE 10: Diffie-Hellman key exchange example.

In this example, then, Alice and Bob will both find the secret key 1 which is, indeed, 36 mod 7 (i.e., GXAXB = 32x3). If an eavesdropper (Eve) was listening in on the information exchange between Alice and Bob, she would learn G, N, YA, and YB which is a lot of information but insufficient to compromise the key; as long as XA and XB remain unknown, K is safe. As stated above, calculating Y = GX is a lot easier than finding X = logG Y.


A short digression on modulo arithmetic. In the paragraph above, we noted that 36 mod 7 = 1. This can be confirmed, of course, by noting that:

36 = 729 = 104*7 + 1

There is a nice property of modulo arithmetic, however, that makes this determination a little easier, namely: (a mod x)(b mod x) = (ab mod x). Therefore, one possible shortcut is to note that 36 = (33)(33). Therefore, 36 mod 7 = (33 mod 7)(33 mod 7) = (27 mod 7)(27 mod 7) = 6*6 mod 7 = 36 mod 7 = 1.


Diffie-Hellman can also be used to allow key sharing amongst multiple users. Note again that the Diffie-Hellman algorithm is used to generate secret keys, not to encrypt and decrypt messages.

5.3. RSA Public Key Cryptography

Unlike Diffie-Hellman, RSA can be used for key exchange as well as digital signatures and the encryption of small blocks of data. Today, RSA is primarily used to encrypt the session key used for secret key encryption (message integrity) or the message's hash value (digital signature). RSA's mathematical hardness comes from the ease in calculating large numbers and the difficulty in finding the prime factors of those large numbers. Although employed with numbers using hundreds of digits, the math behind RSA is relatively straight-forward.

To create an RSA public/private key pair, here are the basic steps:

  1. Choose two prime numbers, p and q. From these numbers you can calculate the modulus, n = pq.
  2. Select a third number, e, that is relatively prime to (i.e., it does not divide evenly into) the product (p-1)(q-1). The number e is the public exponent.
  3. Calculate an integer d from the quotient (ed-1)/[(p-1)(q-1)]. The number d is the private exponent.

The public key is the number pair (n,e). Although these values are publicly known, it is computationally infeasible to determine d from n and e if p and q are large enough.

To encrypt a message, M, with the public key, create the ciphertext, C, using the equation:

The receiver then decrypts the ciphertext with the private key using the equation:

Now, this might look a bit complex and, indeed, the mathematics does take a lot of computer power given the large size of the numbers; since p and q may be 100 digits (decimal) or more, d and e will be about the same size and n may be over 200 digits. Nevertheless, a simple example may help. In this example, the values for p, q, e, and d are purposely chosen to be very small and the reader will see exactly how badly these values perform, but hopefully the algorithm will be adequately demonstrated:

  1. Select p=3 and q=5.
  2. The modulus n = pq = 15.
  3. The value e must be relatively prime to (p-1)(q-1) = (2)(4) = 8. Select e=11.
  4. The value d must be chosen so that (ed-1)/[(p-1)(q-1)] is an integer. Thus, the value (11d-1)/[(2)(4)] = (11d-1)/8 must be an integer. Calculate one possible value, d=3.
  5. Let's suppose that we want to send a message — maybe a secret key — that has the numeric value of 7 (i.e., M=7). [More on this choice below.]
  6. The sender encrypts the message (M) using the public key value (e,n)=(11,15) and computes the ciphertext (C) with the formula C = 711 mod 15 = 1977326743 mod 15 = 13.
  7. The receiver decrypts the ciphertext using the private key value (d,n)=(3,15) and computes the plaintext with the formula M = 133 mod 15 = 2197 mod 15 = 7.

I choose this trivial example because the value of n is so small (in particular, the value M cannot exceed n). But here is a more realistic example using larger d, e, and n values, as well as a more meaningful message; thanks to Barry Steyn for permission to use values from his How RSA Works With Examples page.

Let's say that we have chosen p and q so that we have the following value for n:

14590676800758332323018693934907063529240187237535716439958187
10198734387990053589383695714026701498021218180862924674228281
57022922076746906543401224889672472407926969987100581290103199
31785875366371086235765651050788371429711563734278891146353510
2712032765166518411726859837988672111837205085526346618740053

Let's also suppose that we have selected the public key, e, and private key, d, as follows:

65537

89489425009274444368228545921773093919669586065884257445497854
45648767483962981839093494197326287961679797060891728367987549
93315741611138540888132754881105882471930775825272784379065040
15680623423550067240042466665654232383502922215493623289472138
866445818789127946123407807725702626644091036502372545139713

Now suppose that our message (M) is the character string "attack at dawn" which has the numeric value (after converting the ASCII characters to a bit string and interpreting that bit string as a decimal number) of 1976620216402300889624482718775150.

The encryption phase uses the formula C = Me mod n, so C has the value:

35052111338673026690212423937053328511880760811579981620642802
34668581062310985023594304908097338624111378404079470419397821
53784997654130836464387847409523069325349451950801838615742252
26218879827232453912820596886440377536082465681750074417459151
485407445862511023472235560823053497791518928820272257787786

The decryption phase uses the formula M = Cd mod n, so M has the value that matches our original plaintext:

1976620216402300889624482718775150

This more realistic example gives just a clue as to how large the numbers are that are used in the real world implementations. RSA keylengths of 512 and 768 bits are considered to be pretty weak. The minimum suggested RSA key is 1024 bits; 2048 and 3072 bits are even better.

As an aside, Adam Back (http://www.cypherspace.org/~adam/) wrote a two-line Perl script to implement RSA. It employs dc, an arbitrary precision arithmetic package that ships with most UNIX systems:

print pack"C*",split/\D+/,`echo "16iII*o\[email protected]{$/=$z;[(pop,pop,unpack"H*",<> )]}\EsMsKsN0[lN*1lK[d2%Sa2/d0<X+d*lMLa^*lN%0]dsXx++lMlN/dsM0<J]dsJxp"

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Messerschmitt Me 262

World's first operational jet-powered fighter aircraft

The Messerschmitt Me 262, nicknamed Schwalbe (German: "Swallow") in fighter versions, or Sturmvogel (German: "Storm Bird") in fighter-bomber versions, was the world's first operational jet-powered fighter aircraft. Design work started before World War II began, but problems with engines, metallurgy and top-level interference kept the aircraft from operational status with the Luftwaffe until mid-1944. The Me 262 was faster and more heavily armed than any Allied fighter, including the British jet-powered Gloster Meteor. One of the most advanced aviation designs in operational use during World War II, the Me 262's roles included light bomber, reconnaissance and experimentalnight fighter versions.

Me 262 pilots claimed a total of 542 Allied aircraft shot down, although higher claims are sometimes made.[Note 1] The Allies countered its effectiveness in the air by attacking the aircraft on the ground and during takeoff and landing. Strategic materials shortages and design compromises on the Junkers Jumo 004 axial-flow turbojet engines led to reliability problems. Attacks by Allied forces on fuel supplies during the deteriorating late-war situation also reduced the effectiveness of the aircraft as a fighting force. Armament production within Germany was focused on more easily manufactured aircraft.[9] In the end, the Me 262 had a negligible impact on the course of the war as a result of its late introduction and the consequently small numbers put in operational service.

While German use of the aircraft ended with the close of World War II, a small number were operated by the Czechoslovak Air Force until 1951. It also heavily influenced several designs, such as the Sukhoi Su-9 (1946) and Nakajima Kikka. Captured Me 262s were studied and flight-tested by the major powers, and ultimately influenced the designs of post-war aircraft such as the North American F-86 Sabre, MiG-15 and Boeing B-47 Stratojet. Several aircraft survive on static display in museums, and there are several privately built flying reproductions that use modern General Electric J85 engines.

Design and development[edit]

Origins[edit]

Several years before World War II, the Germans foresaw the great potential for aircraft that used the jet engine constructed by Hans Joachim Pabst von Ohain in 1936. After the successful test flights of the world's first jet aircraft—the Heinkel He 178—within a week of the invasion of Poland to start the war, they adopted the jet engine for an advanced fighter aircraft. As a result, the Me 262 was already under development as Projekt 1065 (P.1065) before the start of World War II. The project originated with a request by the Reichsluftfahrtministerium (RLM, Ministry of Aviation) for a jet aircraft capable of one hour's endurance and a speed of at least 850 km/h (530 mph; 460 kn).[11]Woldemar Voigt headed the design team, with Messerschmitt's chief of development, Robert Lusser, overseeing.[11]

Plans were first drawn up in April 1939, and the original design was very different from the aircraft that eventually entered service, with wing root-mounted engines,[11] rather than podded ones, when submitted in June 1939.[11] The progression of the original design was delayed greatly by technical issues involving the new jet engine. Because the engines were slow to arrive, Messerschmitt moved the engines from the wing roots to underwing pods, allowing them to be changed more readily if needed; this would turn out to be important, both for availability and maintenance.[12] Since the BMW 003 jets proved heavier than anticipated, the wing was swept slightly, by 18.5°, to accommodate a change in the center of gravity.[12] Funding for the jet engine program was also initially lacking as many high-ranking officials thought the war could easily be won with conventional aircraft. Among those were Hermann Göring, head of the Luftwaffe, who cut the engine development program to just 35 engineers in February 1940 (the month before the first wooden mock-up was completed);[11]Willy Messerschmitt, who desired to maintain mass production of the piston-powered, 1935-origin Bf 109 and the projected Me 209; and Major GeneralAdolf Galland, who had initially supported Messerschmitt through the early development years, flying the Me 262 himself on 22 April 1943. By that time, problems with engine development had slowed production of the aircraft considerably. One particularly acute problem arose with the lack of an alloy with a melting point high enough to endure the high temperatures involved, a problem that by the end of the war had not been adequately resolved. The aircraft made its first successful flight entirely on jet power on 18 July 1942, powered by a pair of Jumo 004 engines, after a November 1941 flight (with BMW 003s) ended in a double flameout.[14]

The project aerodynamicist on the design of the Me 262 was Ludwig Bölkow. He initially designed the wing using NACAairfoils modified with an elliptical nose section.[15] Later in the design process, these were changed to AVL derivatives of NACA airfoils, the NACA 00011-0.825-35 being used at the root and the NACA 00009-1.1-40 at the tip.[16] The elliptical nose derivatives of the NACA airfoils were used on the horizontal and vertical tail surfaces. Wings were of single-spar cantilever construction, with stressed skins, varying from 3 mm (0.12 in) skin thickness at the root to 1 mm (0.039 in) at the tip. To expedite construction, save weight and use less strategic materials, late in the war, wing interiors were not painted. The wings were fastened to the fuselage at four points, using a pair of 20 mm (0.79 in) and forty-two 8 mm (0.31 in) bolts.

In mid-1943, Adolf Hitler envisioned the Me 262 as a ground-attack/bomber aircraft rather than a defensive interceptor. The configuration of a high-speed, light-payload Schnellbomber ("fast bomber") was intended to penetrate enemy airspace during the expected Allied invasion of France. His edict resulted in the development of (and concentration on) the Sturmvogel variant. It is debatable to what extent Hitler's interference extended the delay in bringing the Schwalbe into operation;[19] it appears engine vibration issues were at least as costly, if not more so.[14]Albert Speer, then Minister of Armaments and War Production, in his memoirs claimed Hitler originally had blocked mass production of the Me 262, before agreeing in early 1944. Hitler rejected arguments the aircraft would be more effective as a fighter against the Allied bombers destroying large parts of Germany and wanted it as a bomber for revenge attacks. According to Speer, Hitler felt its superior speed compared to other fighters of the era meant it could not be attacked, and so preferred it for high altitude straight flying.[21]

The Me 262 is often referred to as a "swept wing" design as the production aircraft had a small, but significant leading edge sweep of 18.5° which likely provided an advantage by increasing the critical Mach number.[22] Sweep, uncommon at the time, was added after the initial design of the aircraft. The engines proved heavier than originally expected, and the sweep was added primarily to position the center of lift properly relative to the center of mass. (The original 35° sweep, proposed by Adolf Busemann, was not adopted.)[23] On 1 March 1940, instead of moving the wing backward on its mount, the outer wing was re-positioned slightly aft; the trailing edge of the midsection of the wing remained unswept. Based on data from the AVA Göttingen and wind tunnel results, the inboard section's leading edge (between the nacelle and wing root) was later swept to the same angle as the outer panels, from the "V6" sixth prototype onward throughout volume production.

Test flights[edit]

Testing showed that the Me 262 handled much better than previous fighters such as the Bf 109 or Fw 190. Handling was so improved over the previous aircraft that a report by Major Ernst Englander stated that any Bf 109 pilot could convert to the Me 262 with only an hour of instruction. According to his report, even bomber pilots who converted to fly the Me 262 only required three instruction flights, and less than 5% had any difficulty retraining. The Me 262 had a gentle stall and gentle landing characteristics compared to previous German fighters. Its handling improved with speed and would lose much less speed during turning. It had a cruising speed of 465 mph, which was faster than the top speed of most other fighters of the day. It also had far better visibility in every direction compared to previous German fighters. Due to lack of engine torque, if a single engine was lost the aircraft remained easily controlled and landed without issue. Its only major deficiency was that brakes could not be used until the nose wheel had touched down, because engaging them before would smash the nose wheel strongly into the runway, potentially destroying the nose wheel and the aircraft. The quality of the aircraft was high, with only 10% of aircraft returned for minor defects such as wings being out of alignment by under 1 degree. It could reach 515 mph without issue, although because it could reach extreme speeds in dives, components such as bomb racks would sometimes tear off.[26][unreliable source?]

Test flights began on 18 April 1941, with the Me 262 V1 example, bearing its Stammkennzeichen radio code letters of PC+UA, but since its intended BMW 003turbojets were not ready for fitting, a conventional Junkers Jumo 210 engine was mounted in the V1 prototype's nose, driving a propeller, to test the Me 262 V1 airframe.[27] When the BMW 003 engines were installed, the Jumo was retained for safety, which proved wise as both 003s failed during the first flight and the pilot had to land using the nose-mounted engine alone. The V1 through V4 prototype airframes all possessed what would become an uncharacteristic feature for most later jet aircraft designs, a fully retracting conventional gear setup with a retracting tailwheel—indeed, the very first prospective German "jet fighter" airframe design ever flown, the Heinkel He 280, used a retractable tricycle landing gear from its beginnings and flying on jet power alone as early as the end of March 1941.

Silhouette of the V3 prototype – V1 through V4 similar. Note retracting conventional tail wheel gear

The V3 third prototype airframe, with the code PC+UC, became a true jet when it flew on 18 July 1942 in Leipheim near Günzburg, Germany, piloted by test pilot Fritz Wendel.[28] This was almost nine months ahead of the British Gloster Meteor's first flight on 5 March 1943. Its retracting conventional tail wheel gear (similar to other contemporary piston-powered propeller aircraft), a feature shared with the first four Me 262 V-series airframes, caused its jet exhaust to deflect off the runway, with the wing's turbulence negating the effects of the elevators, and the first takeoff attempt was cut short.

On the second attempt, Wendel solved the problem by tapping the aircraft's brakes at takeoff speed, lifting the horizontal tail out of the wing's turbulence. The aforementioned initial four prototypes (V1-V4) were built with the conventional gear configuration. Changing to a tricycle arrangement—a permanently fixed undercarriage on the fifth prototype (V5, code PC+UE), with the definitive fully retractable nosewheel gear on the V6 (with Stammkennzeichen code VI+AA, from a new code block) and subsequent aircraft corrected this problem.[Note 2]

Test flights continued over the next year, but engine problems continued to plague the project, the Jumo 004 being only marginally more reliable than the lower-thrust (7.83 kN/1,760 lbf) BMW 003. Airframe modifications were complete by 1942 but, hampered by the lack of engines, serial production did not begin until 1944, and deliveries were low, with 28 Me 262s in June, 59 in July, but only 20 in August.[page needed]

By Summer 1943, the Jumo 004A engine had passed several 100-hour tests, with a time between overhauls of 50 hours being achieved.[32] However, the Jumo 004A engine proved unsuitable for full-scale production because of its considerable weight and its high utilization of strategic material (Ni, Co, Mo), which were in short supply. Consequently, the 004B engine was designed to use a minimum amount of strategic materials. All high heat-resistant metal parts, including the combustion chamber, were changed to mild steel (SAE 1010) and were protected only against oxidation by aluminum coating. The total engine represented a design compromise to minimize the use of strategic materials and to simplify manufacture.[32] With the lower-quality steels used in the 004B, the engine required overhaul after just 25 hours for a metallurgical test on the turbine. If it passed the test, the engine was refitted for a further 10 hours of usage, but 35 hours marked the absolute limit for the turbine wheel.[33] While BMW's and Junkers' axial compressor turbojet engines were characterised by a sophisticated design that could offer a considerable advantage – also used in a generalized form for the contemporary American Westinghouse J30 turbojet – the lack of rare materials for the Jumo 004 design put it at a disadvantage compared to the "partly axial-flow" Power Jets W.2/700 turbojet engine which, despite its own largely centrifugal compressor-influenced design, provided (between an operating overhaul interval of 60–65 hours[34]) an operational life span of 125 hours. Frank Whittle concludes in his final assessment over the two engines: "it was in the quality of high temperature materials that the difference between German and British engines was most marked"[35]

Operationally, carrying 2,000 litres (440 imperial gallons; 530 US gallons) of fuel in two 900-litre (200-imperial-gallon; 240-US-gallon) tanks, one each fore and aft of the cockpit; and a 200-litre (44-imperial-gallon; 53-US-gallon) ventral fuselage tank beneath,[Note 3] the Me 262 would have a total flight endurance of 60 to 90 minutes. Fuel was usually J2 (derived from brown coal), with the option of diesel or a mixture of oil and high octane B4 aviation petrol. Fuel consumption was double the rate of typical twin-engine fighter aircraft of the era, which led to the installation of a low-fuel warning indicator in the cockpit that notified pilots when remaining fuel fell below 250 l (55 imp gal; 66 US gal).

Unit cost for an Me 262 airframe, less engines, armament, and electronics, was 87,400 RM.[Note 4] To build one airframe took around 6,400-man-hours.

Operational history[edit]

Me 262 A-1a on display at RAF Cosford. Some A-1a aircraft (including this example), like the A-2a bomber variant, attached additional hardpoints for extra weapons near the ejector chutes of the cannons, such as a bomb rack under each side of the nose.

Introduction[edit]

On 19 April 1944, Erprobungskommando 262 was formed at Lechfeld just south of Augsburg, as a test unit (Jäger Erprobungskommando Thierfelder, commanded by HauptmannWerner Thierfelder) to introduce the Me 262 into service and train a corps of pilots to fly it. On 26 July 1944, Leutnant Alfred Schreiber with the 262 A-1a W.Nr. 130 017 damaged a Mosquito reconnaissance aircraft of No. 540 Squadron RAF PR Squadron, which was allegedly lost in a crash upon landing at an air base in Italy. Other sources state the aircraft was damaged during evasive manoeuvres and escaped.

Major Walter Nowotny was assigned as commander after the death of Thierfelder in July 1944, and the unit redesignated Kommando Nowotny. Essentially a trials and development unit, it mounted the world's first jet fighter operations. Trials continued slowly, with initial operational missions against the Allies in August 1944, and the unit made claims for 19 Allied aircraft in exchange for six Me 262s lost.[43]

Despite orders to stay grounded, Nowotny chose to fly a mission against an enemy bomber formation flying some 9,100 m (30,000 ft) above, on 8 November 1944. He claimed two P-51Ds destroyed before suffering engine failure at high altitude. Then, while diving and trying to restart his engines, he was attacked by other Mustangs, forced to bail out, and died. The Kommando was then withdrawn for further flight training and a revision of combat tactics to optimise the Me 262's strengths.[citation needed]

On 26 November 1944, a Me 262A-2a Sturmvogel of III.Gruppe/KG 51 'Edelweiß' based at Rheine-Hopsten Air Base near Osnabrück was the first confirmed ground-to-air kill of a jet combat aircraft. The Me 262 was shot down by a Bofors gun of B.11 Detachment of 2875 Squadron RAF Regiment at the RAF forward airfield of Helmond, near Eindhoven. Others were lost to ground fire on 17 and 18 December when the same airfield was attacked at intervals by a total of 18 Me 262s and the guns of 2873 and 2875 Squadrons RAF Regiment damaged several, causing at least two to crash within a few miles of the airfield. In February 1945, a B.6 gun detachment of 2809 Squadron RAF Regiment shot down another Me 262 over the airfield of Volkel. The final appearance of 262s over Volkel was in 1945 when yet another fell to 2809's guns.[45]

By January 1945, Jagdgeschwader 7 (JG 7) had been formed as a pure jet fighter wing, partly based at Parchim[46] although it was several weeks before it was operational. In the meantime, a bomber unit—I Gruppe, Kampfgeschwader 54 (KG(J) 54)—redesignated as such on 1 October 1944[47] through being re-equipped with, and trained to use the Me 262A-2a fighter-bomber for use in a ground-attack role. However, the unit lost 12 jets in action in two weeks for minimal returns.[citation needed]Jagdverband 44 (JV 44) was another Me 262 fighter unit, of squadron (Staffel) size given the low numbers of available personnel, formed in February 1945 by Lieutenant General Adolf Galland, who had recently been dismissed as Inspector of Fighters. Galland was able to draw into the unit many of the most experienced and decorated Luftwaffe fighter pilots from other units grounded by lack of fuel.

During March, Me 262 fighter units were able, for the first time, to mount large-scale attacks on Allied bomber formations. On 18 March 1945, thirty-seven Me 262s of JG 7 intercepted a force of 1,221 bombers and 632 escorting fighters. They shot down 12 bombers and one fighter for the loss of three Me 262s. Although a 4:1 ratio was exactly what the Luftwaffe would have needed to make an impact on the war, the absolute scale of their success was minor, as it represented only 1% of the attacking force.

In the last days of the war, Me 262s from JG 7 and other units were committed in ground assault missions, in an attempt to support German troops fighting Red Army forces. Just south of Berlin, halfway between Spremberg and the German capital, Wehrmacht's 9th Army (with elements from the 12 Army and 4th Panzer Army) was assaulting the Red Army's 1st Ukrainian Front. To support this attack, on 24 April, JG 7 dispatched thirty-one Me 262s on a strafing mission in the Cottbus-Bautzen area. Luftwaffe pilots claimed six lorries and seven Soviet aircraft, but three German jets were lost. On the evening of 27 April, thirty-six Me 262s from JG 7, III.KG(J)6 and KJ(J)54 were sent against Soviet forces that were attacking German troops in the forests north-east of Baruth. They succeeded in strafing 65 Soviet lorries, after which the Me 262s intercepted low flying Il-2 Sturmoviks searching for German tanks. The jet pilots claimed six Sturmoviks for the loss of three Messerschmitts. During operations between 28 April and 1 May Soviet fighters and ground fire downed at least ten more Me 262s from JG 7.[49] However, JG 7 managed to keep its jets operational until the end of the war. And on 8 May, at around 4:00 p.m. Oblt. Fritz Stehle of 2./JG 7, while flying a Me 262 on the Erzgebirge, attacked a formation of Soviet aircraft. He claimed a Yakovlev Yak-9, but the plane shot down was probably a P-39 Airacobra. Soviet records show that they lost two Airacobras, one of them probably downed by Stehle, who would thus have scored the last Luftwaffe air victory of the war.[50]

Me 262B-1a/U1 night fighter, Wrknr. 110306, with FuG 218 Neptunantennae in the nose and second seat for a radar operator. This airframe was surrendered to the RAF at Schleswig in May 1945 and taken to the UK for testing.

Several two-seat trainer variants of the Me 262, the Me 262 B-1a, had been adapted through the Umrüst-Bausatz 1 factory refit package as night fighters, complete with on-board FuG 218 Neptun high-VHF band radar, using Hirschgeweih ("stag's antlers") antennae with a set of dipole elements shorter than the Lichtenstein SN-2 had used, as the B-1a/U1 version. Serving with 10. StaffelNachtjagdgeschwader 11, near Berlin, these few aircraft (alongside several single-seat examples) accounted for most of the 13 Mosquitoes lost over Berlin in the first three months of 1945.[51] Intercepts were generally or entirely made using Wilde Sau methods, rather than AI radar-controlled interception. As the two-seat trainer was largely unavailable, many pilots made their first jet flight in a single-seater without an instructor.[52]

Despite its deficiencies, the Me 262 clearly marked the beginning of the end of piston-engined aircraft as effective fighting machines. Once airborne, it could accelerate to speeds over 850 km/h (530 mph), about 150 km/h (93 mph) faster than any Allied fighter operational in the European Theater of Operations.[53]

The Me 262's top ace[Note 5] was probably HauptmannFranz Schall with 17 kills, including six four-engine bombers and ten P-51 Mustang fighters, although fighter ace OberleutnantKurt Welter claimed 25 Mosquitos and two four-engine bombers shot down by night and two further Mosquitos by day. Most of Welter's claimed night kills were achieved by eye, even though Welter had tested a prototype Me 262 fitted with FuG 218 Neptun radar. Another candidate for top ace on the aircraft was OberstleutnantHeinrich Bär, who is credited with 16 enemy aircraft[54] while flying Me262s out of his total of 240 aircraft shot down.[55]

Anti-bomber tactics[edit]

The other main USAAF bomber was the B-24 Liberator. This aircraft "Do Bunny" was shot down by a Me 262 on 25 March 1945 over Soltau, Germany

The Me 262 was so fast that German pilots needed new tactics to attack Allied bombers. In the head-on attack, the combined closing speed of about 320 m/s (720 mph) was too high for accurate shooting, with ordnance that could only fire about 44 shells a second (650 rounds/min from each cannon) in total from the quartet of them. Even from astern, the closing speed was too great to use the short-ranged quartet of MK 108 cannon to maximum effect. Therefore, a roller-coaster attack was devised. The Me 262s approached from astern and about 1,800 m higher (5,900 ft) than the bombers. From about five km behind (3.1 mi), they went into a shallow dive that took them through the escort fighters with little risk of interception. When they were about 1.5 km astern (0.93 mi) and 450 m (1,480 ft) below the bombers, they pulled up sharply to reduce speed. On levelling off, they were one km astern (1,100 yd) and overtaking the bombers at about 150 km/h (93 mph), well placed to attack them.[56]

Since the 30mm MK 108 cannon's short barrels and low muzzle velocity (only 540 m/s (1,900 km/h; 1,200 mph)) rendered it inaccurate beyond 600 m (660 yd; 2,000 ft), coupled with the jet's velocity, which required breaking off at 200 m (220 yd; 660 ft) to avoid colliding with the target, Me 262 pilots normally commenced firing at 500 m (550 yd; 1,600 ft).[57] Gunners of Allied bomber aircraft found their electrically powered gun turrets had problems tracking the jets. Target acquisition was difficult because the jets closed into firing range quickly and remained in firing position only briefly, using their standard attack profile, which proved more effective.[58]

Mock-up of an Me 262A-1a/R7 with R4M underwing rocket racks on display at the Technikmuseum Speyer, Germany.

A prominent Royal Navy test pilot, Captain Eric Brown, chief naval test pilot and commanding officer of the Captured Enemy Aircraft Flight Royal Aircraft Establishment, who tested the Me 262 noted:

This was a Blitzkrieg aircraft. You whack in at your bomber. It was never meant to be a dogfighter, it was meant to be a destroyer of bombers... The great problem with it was it did not have dive brakes. For example, if you want to fight and destroy a B-17, you come in on a dive. The 30mm cannon were not so accurate beyond 600 metres [660 yd; 2,000 ft]. So you normally came in at 600 yards [550 m; 1,800 ft] and would open fire on your B-17. And your closing speed was still high and since you had to break away at 200 metres [220 yd; 660 ft] to avoid a collision, you only had two seconds firing time. Now, in two seconds, you can't sight. You can fire randomly and hope for the best. If you want to sight and fire, you need to double that time to four seconds. And with dive brakes, you could have done that.[57]

Eventually, German pilots developed new combat tactics to counter Allied bombers' defences. Me 262s, equipped with up to 24 unguided folding-fin R4M rockets—12 in each of two underwing racks, outboard of the engine nacelle—approached from the side of a bomber formation, where their silhouettes were widest, and while still out of range of the bombers' machine guns, fired a salvo of rockets with strongly brisantHexogen-filled warheads, exactly the same explosive in the shells fired by the Me 262A's quartet of MK 108 cannon. One or two of these rockets could down even the famously rugged Boeing B-17 Flying Fortress,[59] from the "metal-shattering" brisant effect of the fast-flying rocket's 520 g (18 oz) explosive warhead. The much more massive BR 21 large-calibre rockets, used from their tubular launchers in undernose locations for an Me 262A's use (one either side of the nosewheel well) were only as fast as the MK 108's shells.

Though this broadside-attack tactic was effective, it came too late to have a real effect on the war, and only small numbers of Me 262s were equipped with the rocket packs. Most of those so equipped were Me 262A-1a models, members of Jagdgeschwader 7. This method of attacking bombers became the standard, and mass deployment of Ruhrstahl X-4 guided missiles was cancelled. Some nicknamed this tactic the Luftwaffe's Wolf Pack, as the fighters often made runs in groups of two or three, fired their rockets, then returned to base. On 1 September 1944, USAAF GeneralCarl Spaatz expressed the fear that if greater numbers of German jets appeared, they could inflict losses heavy enough to force cancellation of the Allied bombing offensive by daylight.[62]

Counter-jet tactics[edit]

This airframe, Wrknr. 111711, was the first Me 262 to come into Allied hands when its German test pilot defected on 31 March 1945. The aircraft was then shipped to the United States for testing.

The Me 262 was difficult to counter because its high speed and rate of climb made it hard to intercept. However, as with other turbojet engines at the time, the Me 262's engines did not provide sufficient thrust at low airspeeds and throttle response was slow, so that in certain circumstances such as takeoff and landing the aircraft became a vulnerable target. Another disadvantage that pioneering jet aircraft of the World War II era shared, was the high risk of compressor stall and if throttle movements were too rapid, the engine(s) could suffer a flameout. The coarse opening of the throttle would cause fuel surging and lead to excessive jet pipe temperatures. Pilots were instructed to operate the throttle gently and avoid quick changes. German engineers introduced an automatic throttle regulator later in the war but it only partly alleviated the problem.[citation needed]

The plane had, by contemporary standards, a high wing loading (294.0 kg/m2, 60.2 lbs/ft2) that required higher takeoff and landing speeds. Due to poor throttle response, the engines' tendency for airflow disruption that could cause the compressor to stall was ubiquitous. The high speed of the Me 262 also presented problems when engaging enemy aircraft, the high-speed convergence allowing Me 262 pilots little time to line up their targets or acquire the appropriate amount of deflection. This problem faces any aircraft that approaches another from behind at much higher speed, as the slower aircraft in front can always pull a tighter turn, forcing the faster aircraft to overshoot.[citation needed]

I passed one that looked as if it was hanging motionless in the air (I am too fast!). The one above me went into a steep right-hand turn, his pale blue underside standing out against the purple sky. Another banked right in front of the Me's nose. Violent jolt as I flew through his airscrew eddies. Maybe a wing's length away. That one in the gentle left-hand curve! Swing her round. I was coming from underneath, eye glued to the sight (pull her tighter!). A throbbing in the wings as my cannon pounded briefly. Missed him. Way behind his tail. It was exasperating. I would never be able to shoot one down like this. They were like a sack of fleas. A prick of doubt: is this really such a good fighter? Could one in fact, successfully attack a group of erratically banking fighters with the Me 262?

— Johannes Steinhoff, Luftwaffe fighter ace[64]

Luftwaffe pilots eventually learned how to handle the Me 262's higher speed and the Me 262 soon proved a formidable air superiority fighter, with pilots such as Franz Schall managing to shoot down seventeen enemy fighters in the Me 262, ten of them American P-51 Mustangs. Other notable Me 262 aces included Georg-Peter Eder, with twelve enemy fighters to his credit (including nine P-51s), Erich Rudorffer also with twelve enemy fighters to his credit, Walther Dahl with eleven (including three Lavochkin La-7s and six P-51s) and Heinz-Helmut Baudach with six (including one Spitfire and two P-51s) amongst many others.[citation needed]

Pilots soon learned that the Me 262 was quite maneuverable despite its high wing loading and lack of low-speed thrust, especially if attention was drawn to its effective maneuvering speeds. The controls were light and effective right up to the maximum permissible speed and perfectly harmonised. The inclusion of full span automatic leading-edge slats,[Note 6] something of a "tradition" on Messerschmitt fighters dating back to the original Bf 109's outer wing slots of a similar type, helped increase the overall lift produced by the wing by as much as 35% in tight turns or at low speeds, greatly improving the aircraft's turn performance as well as its landing and takeoff characteristics.[67] As many pilots soon found out, the Me 262's clean design also meant that it, like all jets, held its speed in tight turns much better than conventional propeller-driven fighters, which was a great potential advantage in a dogfight as it meant better energy retention in maneuvers.[68][69]

January 1945 Me-262 being shot down. Note jettisoned canopy and empty cockpit. As seen from USAAFP-51 Mustang gun camera

Too fast to catch for the escorting Allied fighters, the Me 262s were almost impossible to head off. [Note 7] As a result, Me 262 pilots were relatively safe from the Allied fighters, as long as they did not allow themselves to get drawn into low-speed turning contests and saved their maneuvering for higher speeds. Combating the Allied fighters could be effectively done the same way as the U.S. fighters fought the more nimble, but slower, Japanese fighters in the Pacific.[citation needed]

Allied pilots soon found that the only reliable way to destroy the jets, as with the even faster Me 163B Komet rocket fighters, was to attack them on the ground or during takeoff or landing. Luftwaffe airfields identified as jet bases were frequently bombed by medium bombers, and Allied fighters patrolled over the fields to attack jets trying to land. The Luftwaffe countered by installing extensive Flak alleys of anti-aircraft guns along the approach lines to protect the Me 262s from the ground—and by providing top cover during the jets' takeoff and landing with the most advanced Luftwaffe single-engined fighters, the Focke-Wulf Fw 190D and (just becoming available in 1945) Focke-Wulf Ta 152H.[71] Nevertheless, in March–April 1945, Allied fighter patrol patterns over Me 262 airfields resulted in numerous jet losses.[citation needed]

As the Me 262A's pioneering Junkers Jumo 004axial-flowjet engines needed careful nursing by their pilots, these jet aircraft were particularly vulnerable during takeoff and landing.[72] Lt. Chuck Yeager of the 357th Fighter Group was one of the first American pilots to shoot down an Me 262, which he caught during its landing approach.[73][74] On 7 October 1944, Lt. Urban Drew of the 365th Fighter Group shot down two Me 262s that were taking off, while on the same day Lt. Col. Hubert Zemke, who had transferred to the Mustang equipped 479th Fighter Group, shot down what he thought was a Bf 109, only to have his gun camera film reveal that it may have been an Me 262.[75] On 25 February 1945, Mustangs of the 55th Fighter Group surprised an entire Staffel of Me 262As at takeoff and destroyed six jets.[76]

The British Hawker Tempest scored several kills against the new German jets, including the Messerschmitt Me 262. Hubert Lange, a Me 262 pilot, said: "the Messerschmitt Me 262's most dangerous opponent was the British Hawker Tempest—extremely fast at low altitudes, highly manoeuvrable and heavily armed."[77] Some were destroyed with a tactic known to the Tempest-equipped No. 135 Wing RAF as the "Rat Scramble":[78] Tempests on immediate alert took off when an Me 262 was reported airborne. They did not intercept the jet, but instead flew towards the Me 262 and Ar 234 base at Hopsten air base.[79][Note 8] The aim was to attack jets on their landing approach, when they were at their most vulnerable, travelling slowly, with flaps down and incapable of rapid acceleration. The German response was the construction of a "flak lane" of over 150 emplacements of the 20 mm Flakvierling quadruple autocannon batteries at Rheine-Hopsten to protect the approaches.[80][Note 9] After seven Tempests were lost to flak at Hopsten in a week, the "Rat Scramble" was discontinued.[81]

High-speed research[edit]

Adolf Busemann had proposed swept wings as early as 1935; Messerschmitt researched the topic from 1940. In April 1941, Busemann proposed fitting a 35° swept wing (Pfeilflügel II, literally "arrow wing II") to the Me 262, the same wing-sweep angle later used on both the American F-86 Sabre and Soviet Mikoyan-Gurevich MiG-15 fighter jets. Though this was not implemented, he continued with the projected HG II and HG III (Hochgeschwindigkeit, "high-speed") derivatives in 1944, designed with a 35° and 45° wing sweep, respectively.

Interest in high-speed flight, which led him to initiate work on swept wings starting in 1940, is evident from the advanced developments Messerschmitt had on his drawing board in 1944. While the Me 262 V9 Hochgeschwindigkeit I (HG I) flight-tested in 1944 had only small changes compared to combat aircraft, most notably a low-profile canopy—tried as the Rennkabine (literally "racing cabin") on the ninth Me 262 prototype for a short time—to reduce drag, the HG II and HG III designs were far more radical. The projected HG II combined the low-drag canopy with a 35° wing sweep and a V-tail (butterfly tail). The HG III had a conventional tail, but a 45° wing sweep and turbines embedded in the wing roots.

Messerschmitt also conducted a series of flight tests with the series production Me 262. Dive tests determined that the Me 262 went out of control in a dive at Mach 0.86, and that higher Mach numbers would cause a nose-down trim that the pilot could not counter. The resulting steepening of the dive would lead to even higher speeds and the airframe would disintegrate from excessive negative g loads.[citation needed]

Messerschmitt believed the HG series of Me 262 derivatives was capable of reaching transonic Mach numbers in level flight, with the top speed of the HG III being projected as Mach 0.96 at 6,000 m (20,000 ft) altitude.[85] After the war, the Royal Aircraft Establishment, at that time one of the leading institutions in high-speed research, re-tested the Me 262 to help with British attempts at exceeding Mach 1. The RAE achieved speeds of up to Mach 0.84 and confirmed the results from the Messerschmitt dive-tests. The Soviets ran similar tests.

After Willy Messerschmitt's death in 1978, the former Me 262 pilot Hans Guido Mutke claimed to have exceeded Mach 1 on 9 April 1945 in a Me 262 in a "straight-down" 90° dive. This claim relies solely on Mutke's memory of the incident, which recalls effects other Me 262 pilots observed below the speed of sound at high indicated airspeed, but with no altitude reading required to determine the speed. The pitot tube used to measure airspeed in aircraft can give falsely elevated readings as the pressure builds up inside the tube at high speeds. The Me 262 wing had only a slight sweep, incorporated for trim (center of gravity) reasons and likely would have suffered structural failure due to divergence at high transonic speeds. One airframe—the aforementioned Me 262 V9, Werknummer 130 004, with Stammkennzeichen of VI+AD, was prepared as the HG I test airframe with the low-profile Rennkabine racing-canopy and may have achieved an unofficial record speed for a turbojet-powered aircraft of 975 km/h (606 mph), altitude unspecified,[87] even with the recorded wartime airspeed record being set on 6 July 1944, by another Messerschmitt design—the Me 163B V18 rocket fighter setting a 1,130 km/h (700 mph) record, but landing with a nearly disintegrated rudder surface.[88][89]

Production[edit]

Underground manufacture of Me 262s

About 1,400 planes were produced, but a maximum of 200 were operational at any one time. According to sources they destroyed from 300 to 450 enemy planes, with the Allies destroying about one hundred Me 262s in the air.[71] While Germany was bombed intensively, production of the Me 262 was dispersed into low-profile production facilities, sometimes little more than clearings in the forests of Germany and occupied countries. From the end of February to the end of March 1945, approximately sixty Me 262s were destroyed in attacks on Obertraubling and thirty at Leipheim;[90] the Neuburg jet plant itself was bombed on 19 March 1945.[91]

Large, heavily protected underground factories were constructed – as with the partly-buried Weingut I complex for Jumo 004 jet engine production – to take up production of the Me 262, safe from bomb attacks. A disused mine complex under the Walpersberg mountain was adapted for the production of complete aircraft. These were hauled to the flat top of the hill where a runway had been cleared and flown out. Between 20 and 30 Me 262s were built here, the underground factory being overrun by Allied troops before it could reach a meaningful output. Wings were produced in Germany's oldest motorway tunnel at Engelberg, to the west of Stuttgart. At B8 Bergkristall-Esche II, a vast network of tunnels was excavated beneath St. Georgen/Gusen, Austria, where slave labourers of concentration camp Gusen II produced fully equipped fuselages for the Me 262 at a monthly rate of 450 units on large assembly lines from early 1945.[92] Gusen II was known as one of the harshest concentration camps; the typical life expectancy was six months.[93] An estimated 35,000 to 50,000 people died on the forced labour details for the Me 262.[94]

Postwar history[edit]

After the end of the war, the Me 262 and other advanced German technologies were quickly swept up by the Soviets, British and Americans, as part of the USAAF's Operation Lusty. Many Me 262s were found in readily repairable condition and were confiscated. The Soviets, British and Americans wished to evaluate the technology, particularly the engines.

During testing, the Me 262 was found to be faster than the British Gloster Meteor jet fighter, and had better visibility to the sides and rear (mostly due to the canopy frames and the discoloration caused by the plastics used in the Meteor's construction), and was a superior gun platform to the Meteor F.1 which had a tendency to snake at high speed and exhibited "weak" aileron response.[95] The Me 262 had a shorter range than the Meteor and had less reliable engines.

The USAAF compared the P-80 Shooting Star and Me 262, concluding that the Me 262 was superior in acceleration and speed, with similar climb performance. The Me 262 appeared to have a higher critical Mach number than any American fighter.[96]

The Americans also tested a Me 262A-1a/U3 unarmed photo reconnaissance version, which was fitted with a fighter nose and a smooth finish. Between May and August 1946, the aircraft completed eight flights, lasting four hours and forty minutes. Testing was discontinued after four engine changes were required during the course of the tests, culminating in two single-engine landings.[97] These aircraft were extensively studied, aiding development of early US, British and Soviet jet fighters. The F-86, designed by engineerEdgar Schmued, used a slat design based on the Me 262's.[98]

Avia S-92, Kbely Museum, Prague, 2012.

The Czechoslovak aircraft industry continued to produce single-seat (Avia S-92) and two-seat (Avia CS-92) variants of the Me 262 after World War II. From August 1946, a total of nine S-92s and three two-seater CS-92s were completed and test flown. They were introduced in 1947 and in 1950 were supplied to the 5th Fighter Squadron, becoming the first jet fighters to serve in the Czechoslovak Air Force. These were kept flying until 1951,[4] when they were replaced in service by Soviet jet fighters. Both versions are on display at the PragueAviation museum in Kbely.

Flyable reproductions[edit]

Me 262 (A-1c) replica of (A1-a), Berlin air show, 2006.

In January 2003, the American Me 262 Project, based in Everett, Washington, completed flight testing to allow the delivery of partially updated spec reproductions of several versions of the Me 262 including at least two B-1c two-seater variants, one A-1c single-seater and two "convertibles" that could be switched between the A-1c and B-1c configurations. All are powered by General Electric CJ610 engines and feature additional safety features, such as upgraded brakes and strengthened landing gear. The "c" suffix refers to the new CJ610 powerplant and has been informally assigned with the approval of the Messerschmitt Foundation in Germany[99] (the Werknummer of the reproductions picked up where the last wartime produced Me 262 left off – a continuous airframe serial number run with a near 60-year production break).

Flight testing of the first newly manufactured Me 262 A-1c (single-seat) variant (Werknummer 501244) was completed in August 2005. The first of these machines (Werknummer 501241) went to a private owner in the southwestern United States, while the second (Werknummer 501244) was delivered to the Messerschmitt Foundation at Manching, Germany. This aircraft conducted a private test flight in late April 2006 and made its public debut in May at the ILA 2006. The new Me 262 flew during the public flight demonstrations.[100] Me 262 Werknummer 501241 was delivered to the Collings Foundation as White 1 of JG 7; this aircraft offered ride-along flights starting in 2008.[101] The third replica, a non-flyable Me 262 A-1c, was delivered to the Evergreen Aviation & Space Museum in May 2010.[102]

Variants[edit]

Note:- U = Umrüst-Bausatz – conversion kit installed at factory level, denoted as a suffix in the form /Un.[103]

Me 262 A-0
Pre-production aircraft fitted with two Jumo 004B turbojet engines, 23 built.
Me 262 A-1a "Schwalbe"
Primary production version, usable as both fighter (interceptor) and fighter-bomber.[27]
Me 262 A-1a/U1
Single prototype with a total of six nose mounted guns, two 20 mm (0.787 in) MG 151/20 cannon, two 30 mm (1.181 in) MK 103 cannon, and two 30 mm (1.181 in) MK 108 cannon.[27]
Me 262 A-1a/U2
Single prototype with FuG 220 Lichtenstein SN-2 90 MHz radar transceiver and Hirschgeweih (stag's antlers) antenna array, for trials as a night-fighter.[27]
Me 262 A-1a/U3
Reconnaissance version modified in small numbers, with Rb 20/30[104] cameras mounted in the nose or alternatively one Rb 20/20[104] and one Rb 75/30[104] (Rb – Reihenbildner – series-picture, topographic camera). Some retained one 30 mm (1.181 in) MK 108 cannon, but most were unarmed.
Me 262 A-1a/U4
Bomber destroyer version, two prototypes with an adapted 50 mm (1.969 in) MK 214 (intended armament) or BK 5 (test ordnance only) anti-tank gun in the nose.[27]
Me 262 A-1a/U5
Heavy jet fighter with six 30 mm (1.181 in) MK 108 cannon in the nose.[27]
Me 262 A-1b
Trio of A-1a evaluation versions, starting with Werknummer 170 078, re-engined with two BMW 003A turbojets in place of the Jumo 004s, maximum speed 800 km/h (500 mph; 430 kn).[105]
Me 262 A-2a "Sturmvogel"
Definitive bomber version retaining only the two lower 30 mm (1.181 in) MK 108 cannon.[27]
Me 262 A-2a/U1
Single prototype with advanced bombsight.
Me 262 A-2a/U2
Two prototypes with glazed nose for accommodating a bombardier.[27]
Me 262 A-3a
Proposed ground-attack version.
Me 262 A-4a
Reconnaissance version.
Me 262 A-5a
Definitive reconnaissance version used in small numbers at end of the war.[27]
Me 262 B-1a
Two-seat trainer.[27]
Me 262 B-1a/U1
Me 262 B-1a trainers converted into provisional night fighters, FuG 218 Neptun radar, with Hirschgeweih (eng:antler) eight-dipole antenna array.[citation needed]
Me 262 B-2
Proposed night fighter version with stretched fuselage.
Me 262C
Proposed development prototypes in four differing designs, meant to augment or replace the Jumo 004 jets with liquid-fueled rocket propulsion, as the "Home Protector" (Heimatschützer) series.
Me 262 C-1a
Single prototype [made from Me 262A Werknummer 130 186] of rocket-boosted interceptor (Heimatschützer I) with Walter HWK 109-509 liquid-fuelled rocket in the tail, first flown with combined jet/rocket power on 27 February 1945.[106]
Me 262 C-2b
Single prototype [made from Me 262A Werknummer 170 074] of rocket-boosted interceptor (Heimatschützer II) with two BMW 003R "combined" powerplants (BMW 003 turbojet, with a single 9.8 kN (2,200 lbf) thrust BMW 109-718 liquid-fuelled rocket engine mounted atop the rear of each jet exhaust) for boosted thrust, only flown once with combined jet/rocket power on 26 March 1945.[107]
Me 262 C-3
Heimatschützer III – proposed version with Jumo 004 turbojet engines replaced with Walter HWK RII-211 Liquid-fuelled rocket engines.[108]
Me 262 C-3a
Heimatschützer IV - a rocket-boosted interceptor with a Walter HWK 109-509S-2 rocket motor housed in a permanent belly pack. Prototypes and initial production aircraft were captured before completion.[109]
Me 262 D-1
Proposed variant to carry Jagdfaust mortars.
Me 262 E-1
Proposed variant based on A-1a/U4 with a 50 mm (1.969 in) MK 114 cannon.[110]
Me 262 E-2
Proposed rocket-armed variant carrying up to 48 × R4M rockets.
Me 262 HG-I
"High Speed" variant, modified A-1a with new "racing" style cockpit and additional pieces were added to wing roots at the front.[111][112][113]
Me 262 HG-II
Second "High Speed" variant, more heavily modified A-1a with "racing" style cockpit and wings swept at 35-degree angle and engine nacelles were moved closer to fuselage. A new butterfly V-shaped tail was tested but was too unstable in wind tunnel tests, so normal tail was kept.[111][112][113]
Me 262 HG-III
Proposed Third "High Speed" variant, only progressed to wind tunnel model stage. This was the last and the pinnacle of the Me-262 aerodynamical possibility, which would have been built from the ground up as a new Me-262 instead of modifying older ones. In the Me-262 HG-III, its wings were swept at 45 degrees, it also had the aforementioned "racing" style cockpit, however, the largest change was the moving of the engine nacelles right into the fuselage side and changing the engines to the more powerful Heinkel HeS 011 engines.[111][112][113]
Me 262 S
Zero-series model for Me 262 A-1a
Me 262 W-1
Provisional designation for Me 262 with 2x 2.7 kN (610 lbf) Argus As 014pulse jet engines
Me 262 W-3
Provisional designation for Me 262 with 2x 4.90 kN (1,102 lbf) "square-intake" Argus As 044pulse jet engines
Me 262 Lorin
Provisional designation for Me 262 with 2x Lorinramjet booster engines in "over-wing" mounts, one above each of the Jumo turbojet nacelles.

Rüstsätze (field modification kits)[edit]

Rüstsatze may be applied to various sub-types of their respective aircraft type, denoted as a suffix in the form /Rn. Data from: Messerschmitt Me 262A Schwalbe[103][114]

/R1: Underfuselage pylon for 500 l (110.0 imp gal; 132.1 US gal) external fuel tank.
/R2: Ratog installation for two Rheinmetall 109-502 solid rocket engines.
/R3: BMW 003R rocket boosted turbojet installation.
/R4: Installation of the FuG 350 Zc Naxos radar warning receiver / detector.
/R5: The standard 4x 30 mm (1.181 in) MK 108 cannon installation.
/R6: Jabo (JagdBomber) equipment, such as bombsights and bomb racks.
/R7: Underwing installation of 12x R4M rockets carried on wooden racks.
/R8: R110BS Air to air rocket installation.
/R9: Ruhrstahl Ru 344 X-4 air-to-air missile installation.

Postwar variants[edit]

Avia S-92[115]
Czech-built Me 262 A-1a (fighter)[116]
Avia CS-92
Czech-built Me 262 B-1a (fighter trainer, two seats)

Reproductions[edit]

A series of reproductions was constructed by American company Legend Flyers (later Me 262 Project) of Everett, Washington.[117] The Jumo 004 engines of the original are replaced by more reliable General Electric CJ610 engines. The first Me 262 reproduction (a two-seater) took off for the first time in December 2002 and the second one in August 2005. This one was delivered to the Messerschmitt Foundation and was presented at the ILA airshow in 2006.[118]

A-1c: American privately built, based on A-1a configuration.
B-1c: American privately built, based on B-1a configuration.
A/B-1c: American privately built, convertible between A-1c and B-1c configuration.

Operators[edit]

Surviving aircraft[edit]

Me 262A-2a (Black X), Australia, 2012
Me 262B-1a/U1 (Red 8), South Africa, 2008
Me 262 B-1a (White 35), at Willow Grove, Pa., in 2007; relocated to and on display in Pensacola, Fl.
Me 262 A-1a/R7, W.Nr.500071 White 3, III./JG 7
Deutsches Museum,[119] Munich, Germany. This aircraft, flown by Hans Guido Mutke while a pilot of 9. Staffel/JG 7, was confiscated by Swiss authorities on 25 April 1945 after Mutke made an emergency landing in Switzerland due to lack of fuel (80 litres were remaining, 35 litres were usually burnt in one minute). Removed (2015?) from main museum for restoration and relocated to: Deutsches Museum Flugwerft Schleissheim, Ferdinand-Schulz-Allee (for navigation systems), 85764 Oberschleissheim, Germany.[120]
Me 262 A-1a
Reconstructed from parts of crashed and incomplete Me 262s. Luftwaffenmuseum der Bundeswehr, Germany.
Me 262 A-1a W.Nr.501232 Yellow 5, 3./KG(J)6
National Museum of the United States Air Force, Wright-Patterson Air Force Base, Dayton, Ohio, US.
Me 262 A-1a/U3 W.Nr.500453
Flying Heritage Collection, Everett, Washington, US, currently in US undergoing restoration to flying condition. It is intended to fly using its original Jumo 004 engines.[121] The aircraft was bought from The Planes of Fame, Chino, California.
Me 262 A-1a/R7 W.Nr.500491 Yellow 7, II./JG 7
National Air and Space Museum, Smithsonian Institution, Washington, DC, US. Possesses twin original underwing racks for 24 R4M unguided rockets.
Me 262 A-1a W.Nr.112372
RAF MuseumCosford, Cosford, United Kingdom.
Me 262 A-2a W.Nr.500200 Black X 9K+XK, 2 Staffel./KG 51
Australian War Memorial, Canberra, Australia. Built at Regensburg in March 1945, same batch from which the Deutsches Museum White 3 was built. Flown by Fahnenjunker Oberfeldwebel Fröhlich and surrendered at Fassberg. It remains the only Me 262 left in existence wearing original (albeit worn, as seen in the picture) colours. Its markings show both the Unit signatures along with the Air Ministry colours applied at Farnborough, where it was allocated reference Air Min 81. Restoration was completed in 1985 and the aircraft was put up on display. The Australian War Memorial's website states that the aircraft "is the only Me 262 bomber variant to survive, and is the only remaining Me 262 wearing its original paint".[123]
Me 262 B-1a/U1, W.Nr.110305 Red 8
South African National Museum of Military History, Johannesburg, South Africa.
Me 262 B-1a, W.Nr.110639 White 35
National Museum of Naval Aviation, Pensacola, Florida (previously at NAS/JRB Willow Grove, Willow Grove, Pennsylvania, US)
Avia S-92
Prague Aviation Museum, Kbely, Prague, Czech Republic.
Avia CS-92
Prague Aviation Museum, Kbely, Prague, Czech Republic.

Specifications (Messerschmitt Me 262 A-1a)[edit]

3-view drawing of the Messerschmitt Me 262.

Data from Quest for Performance[22] Original Messerschmitt documents

General characteristics

  • Crew: 1
  • Length: 10.6 m (34 ft 9 in)
  • Wingspan: 12.6 m (41 ft 4 in)
  • Height: 3.5 m (11 ft 6 in)
  • Wing area: 21.7 m2 (234 sq ft)
  • Aspect ratio: 7.32
  • Empty weight: 3,795 kg (8,367 lb) [125]
  • Gross weight: 6,473 kg (14,271 lb) [125]
  • Max takeoff weight: 7,130 kg (15,719 lb) [125]
  • Powerplant: 2 × Junkers Jumo 004B-1 axial-flow turbojet engines, 8.8 kN (1,980 lbf) thrust each

Performance

  • Maximum speed: 900 km/h (560 mph, 490 kn)
  • Range: 1,050 km (650 mi, 570 nmi)
  • Service ceiling: 11,450 m (37,570 ft)
  • Rate of climb: 20 m/s (3,900 ft/min) at max weight of 7,130 kg (15,720 lb)
  • Thrust/weight: 0.28

Armament

  • Guns: 4 × 30 mm MK 108 cannon (the A-2a had only two cannons)
  • Rockets: 24 × 55 mm (2.2 in) R4M rockets
  • Bombs: 2 × 250 kg (550 lb) bombs or 2 × 500 kg (1,100 lb) bombs (A-2a variant)

Notable appearances in media[edit]

Main article: Messerschmitt Me 262 in fiction

See also[edit]

Aircraft of comparable role, configuration, and era

Related lists

References[edit]

Notes[edit]

  1. ^Morgan and Weal estimate that jet fighters of all types produced 745 victories.
  2. ^The nosewheel was a 66 cm × 16 cm (26.0 in × 6.3 in) item identical to the Bf 109F's main gear wheel, fitted with a Buna rubber tire and pneumatic drum brake.
  3. ^According to Stapfer, the smaller fuel tank had a capacity of up to 237.75 US gallons (197.97 imperial gallons; 900.0 litres).
  4. ^By comparison, a new Volkswagen Type 1 was priced at RM990.[38]
  5. ^For a list of Luftwaffe jet aces, see List of German World War II jet aces
  6. ^The leading edge slats, manufactured by Arwa Strumpfwerke of Auerbach, were divided into three unconnected sections on each wing and each was fastened to the wing by two hinges. The slats lowered the stalling speed of the aircraft to roughly 160 to 170 km/h (86 to 92 kn; 99 to 106 mph) depending on load out. They deployed automatically below 300 km/h (160 kn; 190 mph) on takeoff or landing and at 450 km/h (240 kn; 280 mph) in turn or climb.
  7. ^According to aviation historian Mike Spick, it could take eight Mustangs to neutralize a single Me 262, by continually cutting across the circle inside it. Against multiple jet attackers, an effective defense was simply impossible.[70]
  8. ^Other aircraft based there included Bf 109 and Fw 190-day fighters and Bf 110 and He 219 night fighters. The base was closer to the town of Hopsten than the city of Rheine and is no longer active.
  9. ^As well as the flak guns, several piston engine fighter units based in the area were tasked to cover the jets as they landed.

Citations[edit]

  1. ^ abBalous et al. 1995, p. 53.
  2. ^Kitchen, Martin (2015). Speer: Hitler's Architect. Yale University Press. pp. 213 & 243. ISBN .
  3. ^ abcdeChristopher, John. The Race for Hitler's X-Planes (The Mill, Gloucestershire: History Press, 2013), p. 59.
  4. ^ abChristopher, p. 60.
  5. ^ abChristopher, p. 61.
  6. ^Bölkow, L. "Mit dem Pfeilflügel zum Hochgeschwindigkeitsflug." 50 Jahre Turbostrahlflug. Bonn: DGLR-Bericht, 1989, pp. 225–287.
  7. ^Lednicer, David. The Incomplete Guide to Airfoil Usage. Champaign, Illinois: UIUC Applied Aerodynamics Group, 2010. Retrieved: 19 May 2011.
  8. ^"Stormbirds History."Stormbirds.com.. Retrieved 19 May 2011.
  9. ^Speer 1997, p. 363.
  10. ^ abLoftin, L.K. Jr. Quest for Performance: The Evolution of Modern Aircraft.NASA SP-468. Retrieved: 25 September 2018. Chapter 11 Part 2
  11. ^Christopher, John. The Race for Hitler's X-Planes (History Press, The Mill, Gloucestershire, 2013, p. 48.
  12. ^Operational performance and deployment of Me 262. Major Ernst Englander. 1945.
  13. ^ abcdefghijFord, Roger (2013). Germany's Secret Weapons of World War II. London, United Kingdom: Amber Books. p. 224. ISBN .
  14. ^Warsitz 2009, p. 143.
  15. ^ abMeher-Homji; Cyrus B. (1997). "The Development of the Junkers Jumo 004B". Journal of Engineering for Gas Turbines and Power. 119 (4): 785. doi:10.1115/1.2817055.
  16. ^CIOS XXIV-6 "Gas Turbine Development: BMW-Junkers-Daimler-Benz" London, 1946 p. 24
  17. ^The Gloster Meteor, 1962 p. 28
  18. ^Sir Frank Whittle, Jet: the Story of a Pioneer (1953) pp. 92–93
  19. ^Gilmore, Robert. The KdF Wagens: Germany's Car for the Masses, in VW Trends, February 1992, pp. 36–40.
  20. ^Smith 1971, p. 103.
  21. ^Oliver, Kingsley M. The RAF Regiment at War 1942–1946. Great Britain: Pen & Sword. pp. 111–112.
  22. ^Schwerin-Parchim Flughafen – Pläne (German), Schweriner Volkszeitung, 23 June 2015
  23. ^de Zeng, H.L.; Stankey, D.G.; Creek, Eddie J. (2007). Bomber Units of the Luftwaffe 1933–1945; A Reference Source, Volume 1. Ian Allan Publishing. p. 183. ISBN .
  24. ^Bergstrom, Christer (2008). = Bagration to Berlin: The Final Air Battles in the East: 1944–1945. Great Britain: Ian Allan. p. 123. ISBN .
  25. ^Bergstrom, Christer (2008). = Bagration to Berlin: The Final Air Battles in the East: 1944–1945. Great Britain: Ian Allan. pp. 123–124. ISBN .
  26. ^"Luftwaffe Resource Center – Fighters/Destroyers – A Warbirds Resource Group Site". www.warbirdsresourcegroup.org. Retrieved 11 October 2019.
  27. ^Hecht, Heinrich (1990). The World's First Turbojet Fighter – Messerschmitt Me 262. Schiffer. ISBN .
  28. ^"Messerschmitt Me 262 A-1a Schwalbe (Swallow)". National Air and Space Museum. 22 April 2016. Retrieved 11 October 2019.
  29. ^Miller, David A. (1997). Die Schwertertraeger Der Wehrmacht: Recipients of the Knight's Cross with Oakleaves and Swords. Merriam Press. ISBN .
  30. ^Isby, David C. (19 October 2016). Luftwaffe Fighter Force: The View from the Cockpit. Frontline. ISBN .
  31. ^Spick 1983, p. 112.
  32. ^ abThompson with Smith 2008, p. 233.
  33. ^Hutchinson, Herbert A. (18 October 2018). Inside History of the Usaf Lightweight Fighters, 1900 to 1975. Xlibris Corporation. ISBN .
  34. ^Brown 2006, p. 101.
  35. ^Press, Merriam (2018). World War 2 In Review No. 33: German Airpower. Lulu.com. ISBN .
  36. ^Spick 1983, pp. 112–113.
  37. ^"Theories of Flight devices."centennialofflight.net, 2003. Retrieved: 11 April 2010.
  38. ^Loftin, Laurence K., Jr. "Quest for Performance: The Evolution of Modern Aircraft, Part II: The Jet Age, Chapter 11: Early Jet Fighters, Pioneer jet Fighters." NASA SP-468, NASA Scientific and Technical Information Branch, 2004 via hq.nasa.gov. Retrieved: 11 April 2010.
  39. ^Summary of debriefing of Me-262 test pilot and flight instructor Hans Fey.
  40. ^Spick 1997, p. 165.
  41. ^ abLevine 1992, pp. 158, 185.
  42. ^Forsyth 1996, pp. 149, 194.
  43. ^Niderost, Eric (21 June 2017). "Chuck Yeager: Fighter Pilot". Warfare History Network. Archived from the original on 29 March 2018. Retrieved 29 March 2018.
  44. ^"Encounter Report". 6 November 1944. Archived from the original on 22 February 2018. Retrieved 29 March 2018.
  45. ^Scutts 1994, p. 58.
  46. ^Illustrated Encyclopedia of Aircraft, p. 12.
  47. ^"Hawker Tempest."hawkertempest.se. Retrieved: 1 January 2012.
  48. ^Clostermann 1953, p. 181.
  49. ^"Die Geschichte des Fliegerhorstes"etnp.de. Retrieved: 7 July 2016.
  50. ^"The "Westfalen-Wing" in Rheine-Hopsten Air Base."Archived 15 October 2013 at the Wayback Machineetnep.de. Retrieved: 1 January 2012.
  51. ^Thomas and Shores 1988, p. 129.
  52. ^Carruthers, Bob (2013). Me. 262 Stormbird ascending. Barnsley. ISBN . OCLC 870833813.
  53. ^Flying Review, 1960s, date unknown
  54. ^ de Bie, Rob. "Me 163B Komet – Me 163 Production – Me 163B: Werknummern list."robdebie.home. Retrieved: 28 July 2013.
  55. ^"Me 163."walterwerke.co.uk. Retrieved: 28 August 2010.
  56. ^Englander, Major Ernst. "Summary of debriefing German pilot Hans Fey on operational performance & late war deployment of the Me 262 jet fighter."USAAC, Spring 1945 via zenoswarbirdvideos.com. Retrieved: 11 April 2010.
  57. ^Blue, Allan G. "491st Mission List – June 1944 TO April 1945."Archived 5 September 2008 at the Wayback Machine491st.org. Retrieved: 11 April 2010.
  58. ^Haunschmied et al. 2008, p. 127.
  59. ^"Gusen". www.ushmm.org. United States Holocaust Memorial Museum.
  60. ^Pfeffer, Anshel. "Dark skies". The Jerusalem Post. Retrieved 6 July 2018.
  61. ^Ethell and Price 1994, pp. 97–99.
  62. ^Ethell and Price 1994, p. 180.
  63. ^Butler 1994, p. [page needed].
  64. ^Blair 1980,[page needed]
  65. ^"Aircraft Profiles: Configuration data."Me 262 Project.. Retrieved 29 January 2012.
  66. ^Jim1410. "Me 262 Flys Again!" – via YouTube.
  67. ^"Messerschmitt Me 262 Flight Program."Archived 11 October 2007 at the Wayback MachineCollingsfoundation.org.. Retrieved: 19 May 2011.
  68. ^Bailey, Stewart. "New Me-262 Reproduction lands at the Museum."Evergreen Aviation & Space Museum, 25 June 2010. Retrieved: 7 June 2011.
  69. ^ abParsch, Andreas. "German Military Aircraft Designations (1933–1945)". www.designation-systems.net. Retrieved 14 July 2014.
  70. ^ abc"Luftwaffe Reconnaissance Camera Systems". www.airrecce.co.uk. Archived from the original on 27 May 2014. Retrieved 14 July 2014.
  71. ^Smith, J. Richard; Creek, Eddie (1982). Jet Planes of the Third Reich. Boylston, MA USA: Monogram Aviation Publications. pp. 143–144, 146–147. ISBN .
  72. ^Reddin, Shamus. "Me.262 Heimatschützer I. The Walter 109-509.S1 Assisted Take-Off Unit."Archived 27 April 2009 at the Wayback MachineWalter Website (archived), 27 April 2009. Retrieved: 10 August 2013.
  73. ^"Video of BMW 718 rocket engine test firing on this aircraft."German Jet Power, 1 August 2013. Retrieved: 10 August 2013.
  74. ^Baker, David (1997). Messerschmitt Me 262. Marlborough, Wiltshire [England]: Crowood. ISBN .
  75. ^Reddin, Shamus. "Me.262 Heimatschützer IV. The Walter 109-509.S2 Assisted Take-Off Unit."Archived 27 April 2009 at the Wayback MachineWalter Website (archived), 27 April 2009. Retrieved: 10 August 2013.
  76. ^Green, William (28 March 2016). Famous Fighters Of The Second World War, Volume One. Pickle Partners Publishing. ISBN .
  77. ^ abcLuftwaffe Secret Projects Fighters 1939–1945 by Walter Schick, Ingolf Meyer, Elke Weal, John Weal
  78. ^ abcmesserschmitt Geheimprojekte by Willy radinger and Walter Schick
  79. ^ abcLuftwaffe Secret Projects Fighters 1939–1945 by Walter Schick, Ingolf Meyer, Elke Weal, John Weal p. 85
  80. ^Peçzkowski, Robert (2002).
Источник: [https://torrent-igruha.org/3551-portal.html]
Purchase and Preparation
1.How do I purchase DJI Terra?

DJI Terra Agriculture is available to order at the DJI online store.

DJI Terra Pro, DJI Terra Electricity online version and DJI Terra Cluster offline version are available to order through DJI dealers.

You can also get a license for DJI Terra Agriculture when purchasing MG-1S Advanced, MG-1P or T series agricultural drones.

2.For how long will my DJI Terra license be effective?

Your license comes into effect starting the day the device is bound to DJI Terra.
DJI Terra Agriculture 1 year
DJI Terra Pro 1 year
DJI Terra Pro Permanent
DJI Terra Electricity 1 year
DJI Terra Cluster Permanent

3.What do I need to start using DJI Terra?

1. A Phantom 4 Series drone that supports DJI Terra, several batteries;
2. A laptop, a microSD card and a card reader;
3. A compatible cable (a USB-to-USB cable for Phantom 4, Phantom 4 Pro, Phantom 4 Advanced, a Micro-USB cable for Phantom 4 Pro + V2.0, a USB-C cable for Phantom 4 RTK).

4.What are the computer system requirements for 2D and 3D reconstruction with DJI Terra?

A Windows 7 or above (64 bits) system is required when using the DJI Terra.
Minimum hardware configuration: 16GB RAM and a NVIDIA graphics card with at least 4GB VRAM (must have a compute capability of 3.0 or above).
Recommended hardware configuration: at least 32GB RAM and at least a NVIDIA 1050 Ti.
With these configuration requirements met, every additional 10 GB of RAM will be able to process 4000 additional 4K images. The higher the system configurations, the larger the number of images that can be processed and the faster the reconstructions. The results from the models generated will not be affected by different hardware configurations.

5.Which aircraft are supported by DJI Terra?

Phantom 4 RTK (Remote Controller), Phantom 4 Pro V2.0, Phantom 4 Pro+ V2.0, Phantom 4 Pro, Phantom 4 Advanced and Phantom 4. The Phantom 4 does not support 2D Real-time Mapping.

6.Can I still use the paid features of DJI Terra without an internet connection?

Yes.
For the offline version, once installed, all paid features operate without an internet connection.
For the online version, you must have an internet connection to login, however, you can continue to DJI Terra's paid features offline without logging in again for up to 3 days.

7.Why am I unable to switch the remote controller to PC Mode?

There are three possible reasons cause this problem:
(1)Drivers not installed. Connect the remote controller to DJI Terra via a USB cable. If a yellow exclamation point appears on the Device Manager’s serial port connection, you will need to install a driver; right click to install the driver.
(2)The Phantom 4 Pro+ remote controller (with display) fails to connect with DJI Terra.
(3)Your remote controller has an HDMI module. Only remote controllers without an HDMI module, with a USB port and a Micro USB port, can be switched to PC mode.
*Phantom 4 RTK and Phantom 4 Pro V2.0 series aircraft need not to be switched to remote controller mode.

8.Can I unbind devices from DJI Terra licenses?

You can unbind your DJI Terra Agriculture, Pro, Electricity and Cluster licenses(Except Agras-gift Agriculture license). To unbind, please contact DJI Support. The 1-device licenses can be unbound once in each natural year. 3-device licenses can be unbound twice in each natural year. Once processed, all devices registered under the license will be unbound.

9.What is the one-year free update period?

It is the one-year period from the first date of binding any permanent package after purchase, during which you can update to any version released in that period for free and use all functions included in the package.

10.My software has gone into the paid update period but I have not paid any upgrading and maintenance fee. It has been a few years and I would now like to upgrade it to the latest version. Do I need to pay the upgrading and maintenance fees for the previous years?

Yes.

11.My software has gone into the paid update period but I have not paid any upgrading and maintenance fee. I have since downloaded a new version released during the paid update period. Will I be able to use it?

The paid functions will not be available, but you can still use the basic functions.

12.Will unbinding the software change its first binding date?

It will not.

13.I have two types of licenses: A and B (Pro and Electricity versions, for example). The update validity period is the same on both of them.
The Electricity version has gone into the paid update period but no upgrade and maintenance fee has been paid; the Pro version has also gone into the paid update period but its upgrade and maintenance fee has been paid.
Will I be able to use the functions on the Electricity version?

If you have downloaded and updated to a version released during the paid update period, you can use the functions on the Pro version, but not those on the Electricity version.

14.Can I replace the hardware of my device after the offline version is bound to it?

No, the license is bound to the device's hardware and therefore replacing hardware would invalidate the license.

15.What features are restricted in the offline version?

The following online features are not available in Offline Mode:
- Unlocking GEO Zones
- Map loading and location searching
- Without logging into a DJI account, some flight control functions in DJI Terra are restricted

Flight and Aerial Photography
1.What is the difference between Waypoints Mission, Mapping Mission, Oblique Mission, Corridor Mission and Detailed Inspection Mission?

Waypoints Mission: plan a flight route and capture photos or videos at waypoints along the route.
Mapping Mission: collect images of an area to reconstruct a 2D model.
Oblique Mission: collect images of an area from multiple camera angles to reconstruct a 3D model.
Corridor Mission: collect images of a corridor (e.g. rivers, railroads) to reconstruct a 2D model.
Detailed Inspection Mission: Set target points on a reconstructed model and a flight route will be automatically generated, allowing the aircraft to capture photos at these target points.

2.Why are there 5 flight routes when I plan an Oblique Mission in DJI Terra?

DJI Terra’s Oblique Mission uses 5 flight routes to capture the same amount of data as using 5 cameras simultaneously on a drone. The 5 flight routes correspond to the 5 camera headings – downward, forward, backward, leftward, and rightward.

3.How do I plan flight routes when there is no internet connection and the map cannot be loaded?

If you have access to a mobile device that has an internet connection (such as a cellphone), you can turn on the hotspot so that the laptop can be connected to the internet.
If the site where you are operating has no internet signal, you can pre-plan the flight route while you are indoors and have an internet connection, or manually fly the drone around the area to be mapped to set boundaries points to plan flight routes.

4.What is Ground Sample Distance (GSD)?

In photogrammetry and remote sensing, ground sample distance (GSD) in an aerial digital photo (such as an orthophoto) of the ground is the actual distance on the ground captured as represented by pixels. The unit is cm/pixel.

5.In the Mapping Mission page, what does Mission Relative Height in Advanced Settings mean? How is it different from Mission Altitude in Basic Settings?

Mission Relative Height in Advanced Settings is the height of the takeoff point relative to the area being mapped.
Mission Altitude is the height of the drone relative to the area being mapped, which is also how ground sample distance (GSD) is calculated.

6.When do I have to adjust the Mission Relative Height in Advanced Settings?

When there is a large difference between the elevation of the takeoff location and the elevation of the area being mapped, you can adjust the Mission Relative Height in Advanced Settings to ensure that the Mission Altitude is determined considering the elevation of the area being mapped.
Please see the attached illustration: If the drone takes off from a 50 m building marked H1 in the illustration, the area being mapped is marked A, and the expected altitude for aerial data collection is 100 m, you can set the Mission Altitude in Basic Settings to 100 m, and Mission Relative Height in Advanced Settings to 50 m.
Similarly, if the drone takes off from H2 to map area B, which is a hill with an elevation of 40 m, and the expected altitude for aerial data collection is 60 m, then set Mission Altitude to be 60m, and Mission Relative Height to be -40 m.

7.What should I do to ensure accuracy in my missions when collecting data with the Phantom 4 RTK?

1) Conduct your missions in clear weather conditions with high visibility.
2) Check the images and videos for brightness and clarity immediately after your mission.
3) During a surveying mission, avoid areas with strong electromagnetic interference or obstructions to ensure the accuracy of the attitude algorithm of the Phantom 4 RTK. Also make sure that the remote controller is properly linked to the aircraft.
4) Ensure there is enough forward and side overlap. It is recommended to have a forward overlap rate of 80% and a side overlap rate of 70%. Overlap rates can be adjusted depending on the terrain.

8.When should I adjust the overlap rates based on the terrain?

It is recommended to have a forward overlap rate of 80% and a side overlap rate of 70%, which should meet the requirements for most application scenarios. The overlap rate can be increased when the area being mapped has a large difference in elevation to ensure the highest point mapped has enough overlap. When the area mapped is relatively uniform in elevation, the overlap rate can be adjusted lower to reduce the amount of data that needs to be processed, making the mapping mission more efficient. However, it is recommended to keep the forward overlap at a minimum of 65% and side overlap at a minimum of 60%.

9.When I connect DJI Terra to Phantom 4 RTK, the app tells me that I cannot take off because the RTK signal is too weak. What should I do?

It could be that you are operating somewhere with a lot of signal interference or obstructions, which affects the strength of the RTK signal. Try turning off the RTK module and take off manually with the GNSS positioning. Once the drone reaches a height where there is less interference, you can turn on the RTK module and connect to DJI Terra to conduct your flight missions.

10.Which aircraft support Real-time 3D mapping?

Phantom 4 RTK (Remote Controller), Phantom 4 Pro V2.0, Phantom 4 Pro + V2.0. Note: models may be of poor quality be unavailable in environments without RTK signals.

11.Can I plan flight routes for Waypoints Missions or Detailed Inspection Missions based on real-time 3D models?

Yes.

Detailed Inspection
1.What models of aircraft are supported by detailed inspection flight path planning?

Phantom 4 RTK, Matrice 300 RTK

2.Can third-party point cloud files be imported into DJI Terra?

Yes, LAS point cloud files can be imported.

3.Can a third-party LAS point cloud file be imported if it does not contain a coordinate system?

Yes. You should set the coordinate system when you first import the file. If the file uses an arbitrary coordinate system, you need to correct it using third-party point cloud correction software.

4.Can detailed inspection missions be conducted if the aircraft is flown at mission relative altitude?

No, the aircraft needs to be flown at absolute altitude.

5.What are the important things to take note of when planning or executing a detailed inspection mission?

1. Make sure the RTK data sources are consistent when planning or executing a flight path;
2. Flight paths can only be executed when the RTK is in FIX status. During execution, you may set the first waypoint as the hovering inspection point. The mission must be stopped if the location of the inspection point is incorrect.

Building Reconstruction Models
1.Real-time reconstruction did not generate map, or only generated some of the early map.

First make sure if the number of images transmitted differ significantly from the number of images shot. If they do not, you may check the log to see if a “relocalization fail” message has appeared. If so, you need to increase the mission altitude as necessary to enhance the overlap rate.

2.What are the Field, Urban, and Fruit Tree Scenarios in 2D Map?

The Field Scenario is designed to capture data from a relatively flat land, for example rice or wheat fields.
The Urban Scenario is designed for areas with buildings of different heights.
The Fruit Tree Scenario is designed for orchards that might have a large variation of elevations and heights.
The 2D mapping algorithms are optimized for the three specific scenarios, so you can choose the one that best fits your mission type.

3.A large black area appears on a map generated from 2D reconstruction.

1. The head of the aircraft did not turn around during data acquisition, and the intrinsic parameter cx or cy of the aircraft is shown in the aerotriangulation quality report as >5% than half the length and width of the images;
2. The locations cover contrasting terrain, with roofs or hilltops captured in the shots, which resulted in a low overlap rate. You may re-shoot the images as needed.

4.The edges of the building in a map generated from 2D reconstruction are distorted.

1. The overlap rate is too low. You may re-shoot the images as needed;
2. Make sure “Urban” is selected as the reconstruction scenario.

5.Can I create a 2D reconstruction with oblique images?

No.

6.Why is there a large discrepancy between the elevation result in the digital surface model (DSM) of the 2D map generated by DJI Terra and the actual elevation measured via RTK?

The location information on aerial images collected by a drone that’s not equipped with RTK is not the most accurate, which will result in a difference between the elevation in the digital surface model (DSM) and the actual elevation.
When conducting missions with the Phantom 4 RTK, if the 2D map is generated with only the Nadir view images collected, the precision of the DSM will be limited, which is why it is recommended to incorporate oblique imagery in building the 2D map to enhance precision. This can be done by setting the gimbal pitch to -45° and circling the point of interest during flight.

7.How different are the 3D models built at different resolutions? How long does it take to build models at these resolutions?

There are three options for reconstruction resolution: high, medium, and low, which will generate models at full, half, and quarter resolution respectively. The higher the resolution the better the quality of the reconstructed models. The rough ratio of time consumption for reconstruction at high:medium: low resolutions is about 16:4:1.

8.Can DJI Terra crop 2D and 3D models?

Yes, this can be achieved before reconstruction. After aerial triangulation optimization is complete, crop 2D and 3D models by specifying the reconstruction area using the ROI modeling function.

9.Why are there gaps in my model? What are some factors that affect the quality of the reconstruction?

Gaps in the model can be due to missing shots of the area being mapped, or images taken at poor angles. The quality of reconstruction can be affected by factors such as reflective surfaces in the area (water or glass), or large areas of the same color or pattern (white walls, skies).

10.What should I keep in mind when creating reconstructions using images taken by an oblique camera array?

You will need to define the camera parameters of each of the five cameras. The captured photos will be stored in five folders corresponding to each lens.
In a folder, select all photos, right-click and go to Properties, click Details, scroll down to Camera Model, double-click the parameter value box on the right to go into edit mode, enter numbers or letters. Do this in all five folders for the five camears, the names should be different for each camera, for example it can be set to: 1, 2, 3, 4, 5 or A, B, C, D, E.

11.The entire building in a map generated from 3D reconstruction is tilted to one side.

The head of the aircraft did not turn around during data acquisition, and the intrinsic parameter cx or cy of the aircraft is shown in the aerotriangulation quality report as >5% than half the length and width of the images.

12.The texture of the building’s facade in an image generated from 3D reconstruction is blurry.

The tilted shots are missing. You may recapture the images as needed.

13.Repetitive patterns of spots appear on a map result generated from 2D or 3D reconstruction.

The spots may be caused by damage to your SD card or camera.

14.Why did aerotriangulation fail, or why did I lose a large number of photos?

1. Your RAM may be running low. Currently the processing speed is roughly 300-400 images/G, with no block partitions for aerotriangulation. Divide the number of images imported by 300, and see if the result is greater than the current available RAM;
2. The overlap rate of the images is too low. Has the overlap rate been adjusted to a lower level? Were there any big altitude changes? The overlap rate may need to be increased for areas with greater altitude changes;
3. The textures of objects are not captured in the images: Overexposure of water surfaces, white walls, the sky, snowy grounds, stadiums or other large structures under the sun;
4. Repeated texture: Rice fields, solar panels, floor tiles, etc.;
5. A large number of objects were in motion: Crowds, vehicle flows, sea waves, etc.;
6. A large area captured in the image consists of objects not made of diffuse reflective materials: Mirrors, glass, reflective car surfaces, etc.;
7. The angles of view differ greatly between the images (5-camera oblique system). The top-view image has been reconstructed, but most of the images for the tilted angles are lost;
8. Image quality issues: Blurry movements, lack of focus, overexposure, etc.;
9. Non-continuity in the images, missing shots, or importing multiple sets of data not applicable to the same area.

15.What can I do to save a failed aerotriangulation or recover lost photos?

1. Import the images into DJI Terra, and check their 2D locations on the map;
- Multiple missions can be created to reconstruct the images separately if they are not continuous and can be clearly categorized into batches
- You may capture additional images to fill in shots that may have been missed

2. The 2D locations of the images are continuous and do not show noticeable gaps;
- The reconstruction success rate is relatively low for images of large bodies of water such as the ocean; while for rivers and lakes, you should increase your mission altitude and make sure no more than 1/3 of any single photo is covered by water
- You may recapture the images if the locations are in hilly terrain and the overlap rate is lower than 60%. You should fly the aircraft at a higher altitude and ensure a sufficient overlap rate

3. Data was recorded from multiple trips, and the overlap rate between the trips is sufficient. Some trips do not appear in the reconstruction, while each trip can be reconstructed individually.
- The lighting conditions should not differ too much between the environments where the data was acquired. If some trips were recorded in the morning, while others were captured in the afternoon, the software may not be able to merge the data of different trips due to big contrasts in brightness

16.The texture of a glass building is distorted, or holes appear on reflective objects like cars or on white walls or lake surfaces.

1. Glass and car surfaces are not made of diffuse reflective materials. You may try shooting the images at a greater distance;
2. White walls and lake surfaces do not have textures. You may try shooting the images at a greater distance.

17.What files can I get from the 2D maps and 3D models built in DJI Terra?

2D reconstructions:
Results include map tiles shown in the app’s interface, digital orthophoto maps, and digital surface models in the GeoTIFF format used in UTM projections.

3D reconstructions:
Results contain a level of detail model in .osgb, .b3dm, or .s3mb, texture mesh in .ply, .obj, or .i3s, a point cloud in .pnts, .las, or .s3mb, and an aerial triangulation result file in .xml or Terra's own format.

18.What is the accuracy when building 2D maps and 3D models with the Phantom 4 RTK?

When using the Phantom 4 RTK, the absolute accuracy achieved by the 2D maps in DJI Terra is around 1 to 2 times the GSD, which is a similar level of accuracy as other data processing software. When flying at 100m height, the absolute horizontal accuracy of the 2D map is 2-5cm, and the absolute accuracy of the 3D models is within 4cm.

19.What variables might affect the accuracy of the 2D and 3D reconstructions in DJI Terra?

The accuracy of the reconstruction can be affected by factors such as camera distortion, image quality, flight height, side and forward overlap settings, GPS (RTK) positioning accuracy and the area’s texture information.

20.How do I view the results and files from my aerotriangulation results, 2D maps and 3D point cloud or models?

You can click the Open folder button in each Mission to open the file folders where the files generated from the missions are stored. Aerotriangulation results are stored under "AT", 2D maps are stored under “map” and 3D point cloud or models are stored under “models”.
To view log files of reconstruction mission using Standalone computation, use Ctrl + Alt + L.

21.Can I run multiple missions on the same computer?

Due to limitations in the computer’s processing capacity, you can only run multiple reconstructions at the same time. They will be processed in the order in which they are added to the lineup.

22.During reconstruction, a pop-up window that says "Cannot continue to execute code because OpenCL.dll cannot be found. Reinstalling the program may solve this problem. " - What should I do?

Please update the GPU driver.

23.Why is my computer stuck when processing images locally to reconstruct a model? Can I run DJI Terra while running other programs?

To build reconstruction models as quickly as possible, DJI Terra uses all the computer resources available, including the CPU, RAM, and VRAM of the graphics card, which could make the computer slower while running DJI Terra but should not be a problem once the processing is finished.
It is recommended that you don’t run other programs that might be GPU-intensive while running DJI Terra, as doing so could result in failure of model reconstruction.

24.Does DJI Terra support reconstruction of regions of interest?

Yes. After completing an aerotriangulation, you can set your region of interest and begin reconstruction.

25.Are there any requirements for importing .prj files into DJI Terra?

To allow a .prj file to be imported into DJI Terra, you must ensure the file follows a Esri-supported format and its projection or coordinate framework data are described in WKT character strings.

26.Why did I get the error message: “JSON file read error”?

1. Some of the value for horizontal or vertical accuracy in the POS data of your imported images is 0;
2. The horizontal or vertical accuracy for the image GCP is set at 0 (we recommend updating to version 2.2.1 and above which has an automatic fault tolerance mechanism).

27.Can I add an output format after 3D reconstruction is complete?

Yes, after 3D reconstruction is complete, you can continue reconstruction by checking the required output format.

Output Coordinate System
1.What’s the purpose of setting an output coordinate system?

The following reconstruction results can be delivered in specified coordinate systems.
2D Reconstruction Results: dsm.tif、result.tif
3D Reconstruction Results: LAS files, OBJ files, PLY files, OSGB files, PCD files, S3MB files, I3S files. Each file comes with a coordinate system instruction file metadata.xml.

2.Why do I get an “Output Coordinate System Error” pop-up after I set the output coordinate system and click Reconstruct?
This error will pop up if reconstruction results cannot be converted to the specified coordinate system. The output coordinate system has to do with GPS information on the images and the coordinate system the GCPs are in. Here are some scenarios that you might want to consider:
(1) Aerial triangulation without GCPs


(2) Aerial triangulation optimized with GCPs
Ground Control Points (GCPs)
1.What are Ground Control Points? How to obtain Ground Control Points?

Ground Control Points (GCPs) are marked points on the ground with known coordinates and are clearly visible in an image. GCPs can be obtained using photogrammetry methods such as GPS-RTK or a total station.

2.Why use GCPs?

GCPs help increase the robustness and accuracy of aerial triangulation, check the accuracy of the aerial triangulation against actual measurements, and determine absolute orientation by converting the aerial triangulation result into GCPs in the designated coordinate system.

3.What should be noted when importing GCP files?

The GCP data should be in this order: point name, latitude/X, longitude/Y, height/Z, horizontal accuracy, vertical accuracy).Accuracy data is optional. The first row is coordinate data, and each column is separated with a space or a tab. In the projected coordinate system, X represents the East, and Y represents the North.

4.What are the differences between GCPs and check points?

GCPs are used to optimize the result of aerial triangulation. It would take at least three GCPs to ensure absolute orientation for aerial triangulation.
Check points are used to check for the absolute accuracy of aerial triangulation by comparing the error between the result calculated with aerial triangulation and the actual measurements.
It is recommended to use no less than four GCPs for calculation in each target area.
When you have an abundant number of GCPs, you can choose to set some of them as check points to check for accuracy.

5.How accurate should the GCPs be?

GCPs values are used in aerial triangulation, and the accuracy should correspond to the final absolute accuracy that your project needs.
The smaller the accuracy settings, the stronger the GCP’s contribution will be to the triangulation model.

6.What is a GCP reprojection error?

When computing a point and GCPs have been marked on at least 2 images, the 3D coordinates will be calculated and reprojected onto all images in which the point appears. The difference between the marked point and reprojected point on the image is the reprojection error. the average of different reprojection errors is shown in DJI Terra as the reprojection error.

7.What is a GCP 3D error?

The 3D error of a GCP refers to the spatial difference between its measured coordinates and 3D coordinates obtained by conducting space intersection with the elements of interior and exterior orientations of the image.

8.What are some ways to optimize the results after marking a GCP?

Given that the coordinate system in which aerial images and GCPs have been acquired can be converted using DJI Terra, i.e. the images and GCPs use the same coordinate system geodetic datum:
a) For images with high positioning accuracy, for instance, ones acquired using the Phantom 4 RTK, GCP projections will not be far off from actual measurements. Mark the GCPs with reference to their projected results on the image, and then click “aerial triangulation” on the screen.
b) For images with low positioning precision, you can run aerial triangulation first with the imported images that contain GPS information, and then import the measured coordinates of the GCPs. After the first triangulation, you can proceed with marking the GCPs and run an optimization by pressing “optimize” on the screen.

9.What is the difference between aerial triangulation and optimization?

An optimization is done to improve results of aerial triangulation. If a triangulation is done immediately after marking GCPs, check points will also be used in the calculation, which is not ideal. A better process will be: aerial triangulation enter GCP coordinates and mark them against projected coordinates on the image optimize. By doing so, GCPs are used to improve the accuracy of aerial triangulation.

10.I have imported all images and am now on the GCP Management page, but why do I not see the position and attitude information of the camera?

Make sure the positioning and attitude information of the imported images is correct.

11.Why are the GCPs and camera attitude/position not showing up in the right place after importing GCPs?

Make sure the positioning and attitude information on the images are correct, and choose the same coordinate system as the one that the GCPs are set in.

12.Why is the accuracy of check points lower after optimization using GCPs?

The accuracy of aerial triangulation and optimization are affected by three factors: error in GCP marking, error in coordinate measurement, and the distribution and number of GCPs within the mapping area.
We recommend you choose at least four GCPs distributed evenly across the target area. Each GCP should appear in at least four images at different locations, and avoid having it near the edge of an image.

13.Does DJI Terra support GCP processing for images taken with other DJI drones?

Yes.

14.I've imported GCPs, but why aren't they showing up in aerial triangulation?

1. The coordinate systems do not match. Make sure the coordinate system of the GCPs is the same as that of the selected GCPs, and the coordinate system of the imported POS data is the same as the selected POS data.
2. The coordinate systems cannot be converted from one to the other. Make sure the coordinate system of the image POS data can be converted into the coordinate system of the GCPs. If not, please convert systems using a third-party software program.
3. Height errors. Check the height differences between the coordinate systems of the imported POS data and GCPs. If there are errors, adjust them in the POS data settings.

POS Data
1.When do I need to import POS data?

1. If you are looking to acquire results in a particular height or coordinate system (e.g. a local height or coordinate system that might not be included in Terra's existing database) without GCPs.
2. If you are looking to process POS data and GCPs in the same height or coordinate system, you might need to import POS data and GCP data that have already been converted to said system.

2.How do I set the coordinate system and height error of the POS data?

The coordinate system setting of the POS data needs to correspond to the actual system written in the data. Any height errors need to be adjusted for in the settings. You can preview the height values after adjusting all the POS import settings.

3.What should I keep in mind when setting the POS data accuracy?

1. Set to default DJI Terra accuracy. If the images contain RTK information and it is fixed, DJI Terra will read this data automatically and set the accuracy as follows: horizontal accuracy: 0.03 m, elevation accuracy: 0.06 m. If no RTK information is available or if it is not fixed, horizontal accuracy will be set to 2 m and vertical accuracy 10 m.
2. Set accuracy values manually. Edit the horizontal and vertical accuracy values into the POS data files and choose the corresponding column in in the POS import settings.

4.What happens in aerial triangulation calculations if some of the images lack POS data?

These images will not be included in aerial triangulation calculations.

5.Should I turn on POS Constraint for image processing during aerial triangulation?

Generally, you should keep it on, but turn it off if the image POS data and the GCPs are not in the same height system.

Cluster Reconstruction
1.What computer equipment configuration is required for cluster reconstruction?

Please refer to Preparation Before Using DJI Terra available on the download page.

2.How can I set up a local area network (LAN)?

Please refer to Preparation Before Using DJI Terra available on the download page.

3.What is the maximum number of photos that can be processed through cluster reconstruction?

Depending on the highest computer RAM configuration, 1GB of free RAM can handle 8 gigapixels of data (approximately 400 Phantom 4 RTK images).

4.What is a control device? What is a worker device?

Each computer connected to a local network is either a control device or a worker device. A control device assigns reconstruction missions (and also undertakes part of the computing work), while reconstruction algorithms run mainly on worker device.

5.Do control devices need to be bound with a license?

Yes.

6.Do worker devices need to be bound with a license? Can worker devices be replaced?

Binding is not necessary. Worker devices can be replaced as needed.

7.Can control devices be turned on at the same time in the same local area network (LAN)?

Yes.

8.Can the number of worker devices be increased after the cluster version license is activated?

Yes. For details, please refer to Preparation Before Using DJI Terra.

9.Which software should be used to open worker devices?

DJI TERRA ENGINE

10.What is the purpose of the Shared Directory?

It is used to store original image data, temporary outputs and reconstruction outputs.

11.Does aerotriangulation support cluster reconstruction?

Yes.

12.Can Aerotriangulation Cluster Computation increase the speed of aerotriangulation calculation? In what situations is Aerotriangulation Cluster Computation applicable?

1. If Aerotriangulation Cluster Computation is enabled, DJI Terra will automatically estimate the computing speed of the standalone and the cluster and select the more efficient option. If this feature is disabled, DJI Terra will perform the reconstruction in standalone computing mode.
2. It is recommended to enable Aerotriangulation Cluster Computation when the number of photos exceeds 8,000 and three or more worker devices participate in reconstruction.

13.What is the role of the "Distance to Ground/Subjects" parameter?

1. After aerotriangulation block splitting, the blocks need to partially overlap with a reasonable overlap rate. Therefore, the expansion distance of each block needs to be set. The setting of this parameter affects the expansion distance.
2. The larger the block expansion distance, the slower the aerotriangulation calculation. The default value is suitable for most scenarios.

14.What is the limit on photos processed when Aerotriangulation Cluster Computation is enabled?

The limit on processed data is determined by the memory of the control device. In the control device, 1GB of available memory can be used to process about 6,000 images, so a 128GB control device can process about 800,000 images.

15.What is the basis for aerotriangulation block splitting?

DJI Terra performs aerotriangulation block splitting automatically based on the memory of the worker devices participating in the reconstruction. The worker device with the smallest amount of memory affects the size of the blocks (but does not affect the upper limit for processed data).

16.How can I view the working status of worker devices?

The reconstruction mission list displays the status of the worker devices currently participating in the reconstruction.

17.How control device assign the work of worker devices during cluster reconstruction?

Aerotriangulation: Automatically selects the worker device with the highest RAM to perform the aerotriangulation missions;
Block reconstruction: When the number of blocks is larger than the number of worker devices, the worker devices will be used to the maximum extent.

18.In cluster reconstruction, can a worker devices participate in the current reconstruction mission again after being restarted or released?

No. To enable a restarted or released worker devices to participate in the current reconstruction mission, you can stop the mission and re-select the devices before continuing reconstruction.

19.Why is the utilization rate of integrated graphics cards on worker devices higher than that of discrete graphics cards during reconstruction?

Temporarily not to the step of using a discrete graphics card (integrated graphics cards are not used for computing on DJI Terra).

20.The following prompt appears when opening the software: “Unable to continue code execution because MSVCR120.dll could not be found. Reinstalling the program may resolve this issue.”

Download and install the application: https://download.microsoft.com/download/2/E/6/2E61CFA4-993B-4DD4-91DA-3737CD5CD6E3/vcredist_x64.exe

21.No worker device can be found in the Local Network Worker Devices list.

1. Ensure that the Shared Directory of the control devices and worker devices are consistent and the paths are accessible;
2. Close the antivirus software and security software, then try searching again;
3. Disable the firewall of the control and worker devices.
4. Try searching again after disabling the virtual network card (Network Settings → Change Adapter Option → Disable Networks Started with Hyper-V).

22.There are already aerotriangulation results and the photos are stored on the local disk. Will it go through aerotriangulation again if using cluster to do point cloud or model reconstruction?

No, the photos and existing aerotriangulation results will be automatically copied to the network-attached storage (NAS) for cluster reconstruction.

23.This prompt occurs for a worker device: “Script error.”

1. First, check if you are using software such as Microsoft OneDrive, Outlook, Microsoft Teams and Flash. The software can be uninstalled if not needed;

2. If it is needed, you can try:
(1) Updating the above software
(2) Updating the Win10 system
(3) Updating the driver
(4) Performing the setting: IE security policy-allow dynamic scripts
(5) Performing the setting: IE advanced settings-reset

24.Will any problem with a single device affect the reconstruction mission?

A single worker device error will not cause the reconstruction mission to fail. Any failed worker device mission will be redistributed by the control device. If the redistributed worker device also has errors, the reconstruction mission will fail.

25.Do cluster missions support resuming from a breakpoint?

Yes.

26.Where can I get the logs of cluster reconstruction missions?

1. In the control device, open DJI Terra, press Ctrl+Alt+L, find all logs for the corresponding time period of the failed mission in the folder and export the logs;
2. Under the shared directory, find all logs of the log folder [workers_log] corresponding to the mission and export them;
3. SDK_log.txt in the models (3D) or map (2D) folder in the cache directory of that mission.

27.Why are all worker devices in the preparing state at certain stages of reconstruction, while some worker devices are in the working state and the others in the preparing state at certain other stages?

The reconstruction process is divided into several stages which should be carried out in sequence. Some stages are completed independently on the control device, at which point all worker devices will be in the preparing state.
Some stages are split into multiple missions which are then assigned to the worker device for processing. The worker devices that have completed the missions assigned will be in the preparing state, and will enter the next reconstruction stage after the other worker devices have also completed their processing.

Zenmuse L1 LiDAR Point Cloud Process
1.Do I need to purchase a license to use the DJI Terra LiDAR to process point cloud?

No, LiDAR point cloud is a free feature, but if you need to use the point cloud accuracy optimization feature, you need to purchase the license for the professional version or higher.

2.Does LiDAR point cloud mission create 3D models?

No.

3.Which data should be imported when doing the LiDAR point cloud process?
Imported folders must include LiDAR point cloud data, RTK data, IMU data, whereas JPEG data can be imported when needed (select the folder named after data collection time).

4.What would be the format of the output of the route document?
The format for the route document will be in .out, a SBET and a SMRMSG document, and the format definition is as follows:

SBET Format

SMRMSG Format
5.What is the point cloud effective distance? How do I set up a point cloud effective distance? Under which scenes do I need to set up?

1. Point cloud effective distance: The point cloud that exceeds the distance from the LiDAR will be filtered during post-processing.
2. How to set up a point cloud effective distance: Estimate the maximum straight-line distance between the location of LiDAR and the corresponding target area when collecting data.
3. Under which scenes to set up: When reconstructing a closer measuring area, and when distant background areas are inevitably collected, you can set up an effective distance to get a better result for point cloud.

6.What is point cloud accuracy optimization? When do I need to turn on point cloud accuracy optimization?

1. Point cloud accuracy optimization: Optimize point cloud data scanned at different times to make the overall point cloud accuracy higher.
2. When to turn on point cloud accuracy optimization: When it is off, if the results contain obvious layer malposition, turn on the point cloud accuracy optimization feature to fix the problem.

7.What is the default output coordinate system? Can I modify the coordinate?

The default coordinate system is WGS84 and can be modified.

8.How do I process a point cloud file when it is too large?

You are recommended to separate it into multiple tasks for processing.

9.What does the value of the Colorbar reflectivity mean? And what would be the range?

The reflectivity of the measured target is between 0 - 255, where 0 to 150 correspond to the reflectivity within the range of 0 to 100% in the Lambertian reflection model; 151 to 255 correspond to the reflectivity of target objects with retroflection properties.

10.What information does LAS file record?

The 3D coordinates, RGB color, reflectivity, GPS timestamp, number of returns, the actual return number, and scanning angle of the points are recorded, along with the total number of points corresponding to each return, the software and version corresponding to the generated results, and the geographic coordinate system.

11.What output formats of the files does LiDAR point cloud process?

.pnts, .las, .s3mb, .ply, and .pcd

About Zenmuse L1 calibration
1.How often does the Zenmuse L1 device need to be calibrated?

The calibration frequency varies according to actual usage. When the point cloud post-processing results are layered, inaccurate color rendering, or the device is accidentally dropped, you can use the Zenmuse L1 Calibration mode for processing, and then export the calibration file to the remote control for device calibration.

2.How do I plan routes for collecting calibration materials?

It is recommended to use DJI Pilot to plan the route for collecting calibration materials. The requirements for route planning are as follows:
1. Surveying area: A surveying area at least 300m X 300m with obvious texture features and building facades.
2. The oblique photography route is recommended, with the Repeat Scan Mode enabled, a route speed ≥10m/s, a route height of 100m, a forward overlap ratio of ≥80%, and a side overlap ratio of ≥60%.
3. Model coloring must be enabled (when collecting visible-light photos).
4. You can use either RTK or PPK.

3.After the data is imported and the calibration process is completed, how do I check whether the calibration is compliant with the standard?

1. Checkpoints can be set up in the surveying area, so that you can verify the accuracy of checkpoint based on the calibration route reconstruction results. If the accuracy reaches the engineering project accuracy, the calibration is compliant.
2. Observe whether the coloring of the point cloud results is accurate, and no layered.

About Zenmuse P1 calibration
1.How should I design the calibration route and set parameters? Is RTK required for route collection?

The calibration route can be designed using 5-heading tilt-shift photography or traditional 5-route oblique photography.

To achieve a more reliable calibration result, the following parameters are recommended:
- Capturing no less than 500 images
- The front overlap is no less than 80%
- The side overlap is no less than 70%
- The proportion of oblique images is not less than 2/3
- A calibration scenario with a large elevation difference area

RTK is not required, but the quality of calibration results can be verified through RTK in connection with checkpoint layout.

2.After reconstruction is complete, how do I check whether the route data meets the calibration standard?

If RTK positioning data is available for calibration route collection, the accuracy of checkpoints can be verified based on the results of the calibration route reconstruction by deploying checkpoints in the survey area. If the accuracy meets the required engineering accuracy, the calibration meets the standard.

If no RTK positioning data is available for calibration route collection, it is impossible to quantitatively evaluate whether the calibration result meets the standard. However, this can be verified based on the difference between the initial value and the optimized value of camera parameter focal length f and principal points cx, cy for oblique photography reconstruction after camera calibration. If there is no significant difference, the calibration can be considered as meeting the standard.

3.How often should the load device be calibrated?

How often the load device should be calibrated depends on actual use. It is recommended to calibrate the camera using the latest reconstruction calibration file when there is a significant difference between the initial value and the optimized value of camera parameter focal length f and principal points cx, cy in the reconstruction quality report, and the reconstruction result meets the engineering accuracy requirements.

2D Multispectral Reconstruction
1.What results can be exported from a 2D multispectral reconstruction?
2.How are the vegetation indices calculated in the 2D multispectral reconstruction and what do they mean?
3.Does the 2D Multispectral Construction mode also support data from other multispectral cameras other than the P4 Multispectral?

Currently, no.

4.Can I create 2D multispectral reconstructions without importing RGB images?

No. Currently RGB images are required for 2D multispectral reconstructions.

5.Can images of a particular band captured by P4 Multispectral be imported into DJI Terra for 2D multispectral reconstruction?

Yes. You only need to import RGB images and images within the bands required by a particular vegetation index to perform a reconstruction.

6.Is radiometric correction supported by 2D multispectral reconstruction?

Yes, before reconstruction, calibration data can be imported for radiometric correction

7.How many sets of calibration board data are supported for radiation calibration?

Up to three sets of calibration board data are supported.

Other
1.Can I modify the location where my 2D and 3D reconstructions are saved?
Yes. The default path is C:\Users\***(User Name)\Documents\DJI\DJI Terra. You can modify the path by going to setting icon>> setting icon>> Cache directory.
2.Can I import models generated in DJI Terra into other software programs, such as Maya, Blender, SketchUp, and 3ds Max?

Yes, the .obj files generated in DJI Terra can be imported into Maya, Blender, SketchUp, and 3ds Max. Look up tutorials for the specific process for each software.

3.Can I embed a 3D model into a webpage?

Yes, .b3dm, .osgb, .ply and .obj files generated by DJI Terra are universal file formats and can be embedded into webpages. You can find instructions for embedding each of these formats online.

4.Can I use non-aerial images to build 2D or 3D models?

Theoretically they can be used to reconstruct 3D models although the quality might suffer. They cannot be used to build 2D reconstructions.

5.Can I process images taken from non-DJI drones in DJI Terra to build 2D and 3D reconstructions?

Theoretically yes for 3D models, but the results might not be as good as if you were to use DJI drones. The quality of the reconstructions will benefit from GPS or RTK positioning data on the images. Real-time 2D reconstructions are not supported.

6.What are some keyboard shortcuts that I can use in DJI Terra?
7.A prompt appears on DJI Terra saying that the maximum binding limit has been reached.

1. Check if there has been any hardware changes with the computers bound to the software. Any hard disk location changes or CPU replacements will invalidate the previous binding settings;
2. Check if you have bound any hardware device on a cloud server, such as Alibaba Cloud and Tencent Cloud, which will invalidate the previous binding settings.

8.DJI Terra keeps loading and fails to start normally.

1. Check if any other software (or a virus, Trojan horse, adware, etc.) has been installed on your computer that is preventing DJI Terra from establishing an internet connection. This can be solved by resetting the networks of the Windows system.
2. Check if any VPN software has been enabled. If so, disable the VPN or configure the VPN correctly.

9.The system says No license, Contact your local dealer.

You will see the following data in the log:
[GetAvailableFunc] iDate: 1596520841 iCurDate: 1596520513 iEndDate:1596729600
[GetAvailableFunc] Local license out of date.
iDate is the server’s time, and iCurDate is the current time of the user’s computer. The license cannot be used when iDate > iCurDate.
Usually the value of iCurDate should be greater than iDate. It is possible that your computer’s clock is slow. You may try resetting the time. Both Win7 and Win10 support automatic online time calibration. We suggest you enable this feature.

Источник: [https://torrent-igruha.org/3551-portal.html]
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5.4. DES, Breaking DES, and DES Variants

The Data Encryption Standard (DES) started life in the mid-1970s, adopted by the National Bureau of Standards (NBS) [now the National Institute of Standards and Technology (NIST)] as Federal Information Processing Standard 46 (FIPS PUB 46-3) and by the American National Standards Institute (ANSI) as X3.92.

As mentioned earlier, DES uses the Data Encryption Algorithm (DEA), a secret key block-cipher employing a 56-bit key operating on 64-bit blocks. FIPS PUB 81 describes four modes of DES operation: Electronic Codebook (ECB), Cipher Block Chaining (CBC), Cipher Feedback (CFB), and Output Feedback (OFB). Despite all of these options, ECB is the most commonly deployed mode of operation.

NIST finally declared DES obsolete in 2004, and withdrew FIPS PUB 46-3, 74, and 81 (Federal Register, July 26, 2004, 69(142), 44509-44510). Although other block ciphers have replaced DES, it is still interesting to see how DES encryption is performed; not only is it sort of neat, but DES was the first crypto scheme commonly seen in non-governmental applications and was the catalyst for modern "public" cryptography and the first public Feistel cipher. DES still remains in many products — and cryptography students and cryptographers will continue to study DES for years to come.

DES Operational Overview

DES uses a 56-bit key. In fact, the 56-bit key is divided into eight 7-bit blocks and an 8th odd parity bit is added to each block (i.e., a "0" or "1" is added to the block so that there are an odd number of 1 bits in each 8-bit block). By using the 8 parity bits for rudimentary error detection, a DES key is actually 64 bits in length for computational purposes although it only has 56 bits worth of randomness, or entropy (See Section A.3 for a brief discussion of entropy and information theory).

FIGURE 11: DES enciphering algorithm.

DES then acts on 64-bit blocks of the plaintext, invoking 16 rounds of permutations, swaps, and substitutes, as shown in Figure 11. The standard includes tables describing all of the selection, permutation, and expansion operations mentioned below; these aspects of the algorithm are not secrets. The basic DES steps are:

  1. The 64-bit block to be encrypted undergoes an initial permutation (IP), where each bit is moved to a new bit position; e.g., the 1st, 2nd, and 3rd bits are moved to the 58th, 50th, and 42nd position, respectively.

  2. The 64-bit permuted input is divided into two 32-bit blocks, called left and right, respectively. The initial values of the left and right blocks are denoted L0 and R0.

  3. There are then 16 rounds of operation on the L and R blocks. During each iteration (where n ranges from 1 to 16), the following formulae apply:

      Ln = Rn-1
      Rn = Ln-1 ⊕ f(Rn-1,Kn)

    At any given step in the process, then, the new L block value is merely taken from the prior R block value. The new R block is calculated by taking the bit-by-bit exclusive-OR (XOR) of the prior L block with the results of applying the DES cipher function, f, to the prior R block and Kn. (Kn is a 48-bit value derived from the 64-bit DES key. Each round uses a different 48 bits according to the standard's Key Schedule algorithm.)

    The cipher function, f, combines the 32-bit R block value and the 48-bit subkey in the following way. First, the 32 bits in the R block are expanded to 48 bits by an expansion function (E); the extra 16 bits are found by repeating the bits in 16 predefined positions. The 48-bit expanded R-block is then ORed with the 48-bit subkey. The result is a 48-bit value that is then divided into eight 6-bit blocks. These are fed as input into 8 selection (S) boxes, denoted S1,...,S8. Each 6-bit input yields a 4-bit output using a table lookup based on the 64 possible inputs; this results in a 32-bit output from the S-box. The 32 bits are then rearranged by a permutation function (P), producing the results from the cipher function.

  4. The results from the final DES round — i.e., L16 and R16 — are recombined into a 64-bit value and fed into an inverse initial permutation (IP-1). At this step, the bits are rearranged into their original positions, so that the 58th, 50th, and 42nd bits, for example, are moved back into the 1st, 2nd, and 3rd positions, respectively. The output from IP-1 is the 64-bit ciphertext block.

Consider this example using DES in CBC mode with the following 56-bit key and input:

    Key: 1100101 0100100 1001001 0011101 0110101 0101011 1101100 0011010 = 0x6424491D352B6C1A

    Input character string (ASCII/IA5): +2903015-08091765
    Input string (hex): 0x2B323930333031352D3038303931373635

    Output string (hex): 0x9812CB620B2E9FD3AD90DE2B92C6BBB6C52753AC43E1AFA6
    Output character string (BASE64): mBLLYgsun9OtkN4rksa7tsUnU6xD4a+m

Observe that we start with a 17-byte input message. DES acts on eight bytes at a time, so this message is padded to 24 bytes and provides three "inputs" to the cipher algorithm (we don't see the padding here; it is appended by the DES code). Since we have three input blocks, we get 24 bytes of output from the three 64-bit (eight byte) output blocks.

If you want to test this, a really good free, online DES calculator hosted by the Information Security Group at University College London. An excellent step-by-step example of DES can also be found at J. Orlin Grabbe's The DES Algorithm Illustrated page.


NOTE: You'll notice that the output above is shown in BASE64. BASE64 is a 64-character alphabet — i.e., a six-bit character code composed of upper- and lower-case letters, the digits 0-9, and a few punctuation characters — that is commonly used as a way to display binary data. A byte has eight bits, or 256 values, but not all 256 ASCII characters are defined and/or printable. BASE64, simply, takes a binary string (or file), divides it into six-bit blocks, and translates each block into a printable character. More information about BASE64 can be found at my BASE64 Alphabet page or at Wikipedia.

Breaking DES

The mainstream cryptographic community has long held that DES's 56-bit key was too short to withstand a brute-force attack from modern computers. Remember Moore's Law: computer power doubles every 18 months. Given that increase in power, a key that could withstand a brute-force guessing attack in 1975 could hardly be expected to withstand the same attack a quarter century later.

DES is even more vulnerable to a brute-force attack because it is often used to encrypt words, meaning that the entropy of the 64-bit block is, effectively, greatly reduced. That is, if we are encrypting random bit streams, then a given byte might contain any one of 28 (256) possible values and the entire 64-bit block has 264, or about 18.5 quintillion, possible values. If we are encrypting words, however, we are most likely to find a limited set of bit patterns; perhaps 70 or so if we account for upper and lower case letters, the numbers, space, and some punctuation. This means that only about ¼ of the bit combinations of a given byte are likely to occur.

Despite this criticism, the U.S. government insisted throughout the mid-1990s that 56-bit DES was secure and virtually unbreakable if appropriate precautions were taken. In response, RSA Laboratories sponsored a series of cryptographic challenges to prove that DES was no longer appropriate for use.

DES Challenge I was launched in March 1997. It was completed in 84 days by R. Verser in a collaborative effort using thousands of computers on the Internet.

The first DES Challenge II lasted 40 days in early 1998. This problem was solved by distributed.net, a worldwide distributed computing network using the spare CPU cycles of computers around the Internet (participants in distributed.net's activities load a client program that runs in the background, conceptually similar to the SETI @Home "Search for Extraterrestrial Intelligence" project). The distributed.net systems were checking 28 billion keys per second by the end of the project.

The second DES Challenge II lasted less than 3 days. On July 17, 1998, the Electronic Frontier Foundation (EFF) announced the construction of hardware that could brute-force a DES key in an average of 4.5 days. Called Deep Crack, the device could check 90 billion keys per second and cost only about $220,000 including design (it was erroneously and widely reported that subsequent devices could be built for as little as $50,000). Since the design is scalable, this suggests that an organization could build a DES cracker that could break 56-bit keys in an average of a day for as little as $1,000,000. Information about the hardware design and all software can be obtained from the EFF.

The DES Challenge III, launched in January 1999, was broken is less than a day by the combined efforts of Deep Crack and distributed.net. This is widely considered to have been the final nail in DES's coffin.

The Deep Crack algorithm is actually quite interesting. The general approach that the DES Cracker Project took was not to break the algorithm mathematically but instead to launch a brute-force attack by guessing every possible key. A 56-bit key yields 256, or about 72 quadrillion, possible values. So the DES cracker team looked for any shortcuts they could find! First, they assumed that some recognizable plaintext would appear in the decrypted string even though they didn't have a specific known plaintext block. They then applied all 256 possible key values to the 64-bit block (I don't mean to make this sound simple!). The system checked to see if the decrypted value of the block was "interesting," which they defined as bytes containing one of the alphanumeric characters, space, or some punctuation. Since the likelihood of a single byte being "interesting" is about ¼, then the likelihood of the entire 8-byte stream being "interesting" is about ¼8, or 1/65536 (½16). This dropped the number of possible keys that might yield positive results to about 240, or about a trillion.

They then made the assumption that an "interesting" 8-byte block would be followed by another "interesting" block. So, if the first block of ciphertext decrypted to something interesting, they decrypted the next block; otherwise, they abandoned this key. Only if the second block was also "interesting" did they examine the key closer. Looking for 16 consecutive bytes that were "interesting" meant that only 224, or 16 million, keys needed to be examined further. This further examination was primarily to see if the text made any sense. Note that possible "interesting" blocks might be 1hJ5&aB7 or DEPOSITS; the latter is more likely to produce a better result. And even a slow laptop today can search through lists of only a few million items in a relatively short period of time. (Interested readers are urged to read Cracking DES and EFF's Cracking DES page.)

It is well beyond the scope of this paper to discuss other forms of breaking DES and other codes. Nevertheless, it is worth mentioning a couple of forms of cryptanalysis that have been shown to be effective against DES. Differential cryptanalysis, invented in 1990 by E. Biham and A. Shamir (of RSA fame), is a chosen-plaintext attack. By selecting pairs of plaintext with particular differences, the cryptanalyst examines the differences in the resultant ciphertext pairs. Linear plaintext, invented by M. Matsui, uses a linear approximation to analyze the actions of a block cipher (including DES). Both of these attacks can be more efficient than brute force.

DES Variants

Once DES was "officially" broken, several variants appeared. But none of them came overnight; work at hardening DES had already been underway. In the early 1990s, there was a proposal to increase the security of DES by effectively increasing the key length by using multiple keys with multiple passes. But for this scheme to work, it had to first be shown that the DES function is not a group, as defined in mathematics. If DES was a group, then we could show that for two DES keys, X1 and X2, applied to some plaintext (P), we can find a single equivalent key, X3, that would provide the same result; i.e.,

EX2(EX1(P)) = EX3(P)

where EX(P) represents DES encryption of some plaintext P using DES key X. If DES were a group, it wouldn't matter how many keys and passes we applied to some plaintext; we could always find a single 56-bit key that would provide the same result.

Источник: [https://torrent-igruha.org/3551-portal.html]

October 2021 Updates

iOS: Litchi for DJI Mavic / Phantom / Inspire / Spark

Version 2.10.0 / 2.10.1(October 7, 2021)
- added support for Mavic Air 2
- added waypoint mode for Mavic Mini 1 and Mavic Air 2
- Facebook login is no longer supported. If you were using Facebook to log in, please migrate your Litchi account at https://flylitchi.com/facebooklogin
- fixed a bug in Follow mode where the gimbal would not stay on the subject when there are elevation changes
- fixed bug where Litchi Vue would fail to connect
- fixed flickering bug with inspire 2 gimbal
- misc improvements and bug fixes

Android: Litchi for DJI Mavic / Phantom / Inspire / Spark

Version 4.19.0(October 7, 2021)
- added support for Mavic Air 2
- added waypoint mode for Mavic Mini 1 and Mavic Air 2
- added support for a secondary video feed for drones with multiple cameras
- Facebook login is no longer supported. If you were using Facebook to log in, please migrate your Litchi account at https://flylitchi.com/facebooklogin
- fixed a bug in Follow mode where the gimbal would not stay on the subject when there are elevation changes
- misc improvements and bug fixes

November 2020 Updates

iOS: Litchi for DJI Mavic / Phantom / Inspire / Spark

Version 2.9.1(November 24, 2020)
- bug fix
Version 2.9.0(November 20, 2020)
- added support for Mavic Mini 1, all flight modes are supported except waypoint which will come in a future update
- added Follow mode
- Panorama Database has been revamped, stitching is improved and you can now stitch up to 130 megapixels spherical panoramas on iPhone and up to 220 megapixels on iPad Pro
- added new "Auto Stitch Panoramas" general camera setting. When enabled, after shooting a panorama, Litchi will automatically stitch it in low resolution in the background
- added Simulator mode that can be used to simulate a flight, enable/disable it with a long press on the top bar's flight mode (requires a connection to the drone)
- added new "Switch Flight Mode" custom function to switch the Mavic Mini's flight mode
- added new Dynamic Homepoint setting
- added support for Auto Exposure Bracketing (AEB) photo capture mode for Mavic Mini
- AutoPano now shoots 360x110 spherical panoramas compared to 360x90 before
- Mavic 2 Zoom's optical zoom is now correctly reported in the UI
- fixed bug where sharing a panorama on Facebook would fail
- misc improvements and bug fixes

Android: Litchi for DJI Mavic / Phantom / Inspire / Spark

Version 4.18.0(November 20, 2020)
- added support for Mavic Mini 1, all flight modes are supported except waypoint which will come in a future update
- improved Follow mode
- added Simulator mode that can be used to simulate a flight, enable/disable it with a long press on the top bar's flight mode (requires a connection to the drone)
- added new "Switch Flight Mode" custom function to switch the Mavic Mini's flight mode
- added support for Auto Exposure Bracketing (AEB) photo capture mode for Mavic Mini
- AutoPano now shoots 360x110 spherical panoramas compared to 360x90 before
- misc improvements and bug fixes

November 2019 Updates

iOS: Litchi for DJI Mavic / Phantom / Inspire / Spark

Version 2.8.0(November 26, 2019)
- when starting a waypoint mission, you can now choose to start at a specific waypoint rather than from the beginning
- added new "Exit Waypoint Mission on Signal Loss" aircraft setting. When enabled, waypoint missions will end when signal is lost. When that happens, the drone will then execute the failsafe procedure (which can be changed with the "Signal Lost Behavior for Manual Flying" setting)
- added new "Map Auto Zoom" general setting which lets you disable the map auto zoom
- misc improvements and bug fixes
Version 2.7.1(November 12, 2019)
- fixed Facebook login

Android: Litchi for DJI Mavic / Phantom / Inspire / Spark

Version 4.17.0(November 29, 2019)
- added "Over Exposure Warning" general camera setting
- added "Peak Focus Threshold" general camera setting
Version 4.16.0(November 26, 2019)
- when starting a waypoint mission, you can now choose to start at a specific waypoint rather than from the beginning
- added new "Exit Waypoint Mission on Signal Loss" aircraft setting. When enabled, waypoint missions will end when signal is lost. When that happens, the drone will then execute the failsafe procedure (which can be changed with the "Signal Lost Behavior for Manual Flying" setting)
- misc improvements and bug fixes

October 2019 Updates

iOS: Litchi for DJI Mavic / Phantom / Inspire / Spark

Version 2.7.0(October 18, 2019)
- added new mission setting "Photo Capture Interval" that can be used to automatically start an interval capture for the entire mission or between specific waypoints
- misc bug fixes

Android: Litchi for DJI Mavic / Phantom / Inspire / Spark

Version 4.15.0(October 18, 2019)
- added new mission setting "Photo Capture Interval" that can be used to automatically start an interval capture for the entire mission or between specific waypoints
- added support for android 10
- misc bug fixes

Web: Mission Hub

Version 1.4.0(October 18, 2019)
- added new mission setting "Photo Capture Interval" that can be used to automatically start an interval capture for the entire mission or between specific waypoints

August 2019 Updates

iOS: Litchi for DJI Mavic / Phantom / Inspire / Spark

Version 2.6.7(August 27, 2019)
- added new Tracking Quality setting in Track mode, set to High for improved tracking accuracy (only for powerful devices)
- it is now possible to add a POI while a mission is in progress using the custom function "POI at Aircraft"
- misc improvements and bug fixes

Android: Litchi for DJI Mavic / Phantom / Inspire / Spark

Version 4.14.0(August 27, 2019)
- it is now possible to add a POI while a mission is in progress using the custom function "POI at Aircraft"
- misc improvements and bug fixes

June 2019 Updates

iOS: Litchi for DJI Mavic / Phantom / Inspire / Spark

Version 2.6.6(June 10, 2019)
- misc bug fixes and improvements

May 2019 Updates

Android: Litchi for DJI Mavic / Phantom / Inspire / Spark

Version 4.13.0(May 24, 2019)
- added support for the DJI Smart Controller (installation steps)

April 2019 Updates

Android: Litchi for DJI Mavic / Phantom / Inspire / Spark

Version 4.12.0(April 3, 2019)
- bug fixes

February 2019 Updates

iOS: Litchi for DJI Mavic / Phantom / Inspire / Spark

Version 2.6.5(February 25, 2019)
- added support for Apple Maps
- misc improvements and bug fixes

Android: Litchi for DJI Mavic / Phantom / Inspire / Spark

Version 4.11.0(February 25, 2019)
- bug fixes

January 2019 Updates

iOS: Litchi for DJI Mavic / Phantom / Inspire / Spark

Version 2.6.4(January 14, 2019)
- misc bug fixes and improvements

Android: Litchi for DJI Mavic / Phantom / Inspire / Spark

Version 4.10.0(January 11, 2019)
- added support for Mavic 2 Enterprise
- fixed Inspire 2 gimbal bug where it would be forced to switch to Free mode

November 2018 Updates

iOS: Litchi for DJI Mavic / Phantom / Inspire / Spark

Version 2.6.3(November 21, 2018)
- added support for Mavic 2 Enterprise
- updated no fly zone system to support GEO 2.0
- fixed Inspire 2 gimbal bug where it would be forced to switch to Free mode

October 2018 Updates

Web: Mission Hub

Version 1.3.0(October 31, 2018)
- added support for importing Digital Elevation Model (DEM) files

September 2018 Updates

iOS: Litchi for DJI Mavic / Phantom / Inspire / Spark

Version 2.6.2(September 28, 2018)
- fixed VR mode display issue when using iPhone XS Max
Version 2.6.1(September 24, 2018)
- fixed waypoint curve display issue
Version 2.6.0(September 20, 2018)
- added support for Mavic 2 Zoom/Pro

Android: Litchi for DJI Mavic / Phantom / Inspire / Spark

Version 4.9.0(September 20, 2018)
- added support for Mavic 2 Zoom/Pro
- fixed crash on Android 9 Pie
- fixed bug where map zoom/rotate gestures would not always work
- fixed pano bug when 'grid pattern' was set to 'spherical'

Web: Mission Hub

Version 1.2.3(September 20, 2018)
- KML 3D Path export improvements

August 2018 Updates

iOS: Litchi for DJI Mavic / Phantom / Inspire / Spark

Version 2.5.1(August 14, 2018)
- fixed a crash that could happen when starting the app
Version 2.5.0(August 13, 2018)
- added support for Phantom 4 Pro V2
- enabled waypoint and orbit mode for Spark
- added support for Manual Focus mode
- added 'Calibrate Lens' camera setting, can be used to set Infinity Focus
- the custom key 'Focus to Infinity' is now available for all drones with variable focus
- the gimbal pitch angle in degrees is now displayed in the UI
- added camera exposure settings to the VR mode on-screen display
- added 'Transmission Channel' setting for Mavic Air/Spark
- added 'Frequency Band' setting for Phantom 4 Pro V2
- added 'Lock Gimbal when Shooting Photos' setting
- added 'Sync Gimbal Yaw with Aircraft Heading' setting
- added 'Show VPS Height when Used' setting
- fixed an issue where the VR mode would stretch too much on iPhone X
- fixed a display bug with the pause button in waypoint mode

Android: Litchi for DJI Mavic / Phantom / Inspire / Spark

Version 4.8.0(August 13, 2018)
- added support for Phantom 4 Pro V2
- enabled waypoint and orbit mode for Spark
- added support for Manual Focus mode
- added 'Calibrate Lens' camera setting, can be used to set Infinity Focus
- added 'Focus to Infinity' custom function, available for all drones with variable focus
- waypoint missions now show distance info between waypoints
- added shutter and aperture priority exposure modes for drones that support them
- the gimbal pitch angle in degrees is now displayed in the UI
- added camera exposure settings to the VR mode on-screen display
- added 'Transmission Channel' setting for Mavic Air/Spark
- added 'Frequency Band' setting for Phantom 4 Pro V2
- added 'Lock Gimbal when Shooting Photos' setting
- added 'Sync Gimbal Yaw with Aircraft Heading' setting
- added 'Show VPS Height when Used' setting
- added 'Display Secondary Video Feed' setting for Inspire 2 and Matrice series
- added custom function 'Switch Video Feed' for Inspire 2 and Matrice series
- fixed a display bug with the pause button in waypoint mode

July 2018 Updates

Web: Mission Hub

Version 1.2.2(July 20, 2018)
- elevation features are now disabled by default and need to be enabled in the Hub settings before use
Version 1.2.1(July 5, 2018)
- exporting to CSV will now correctly export headings when the mission heading mode is set to "Auto"
- elevation features can now only be used when logged in to a Litchi account
- distance labels between consecutive waypoints now show the 3D distance
- fixed bug where manually editing lat/long would not update the heading of waypoints which focus on a POI

June 2018 Updates

iOS: Litchi for DJI Mavic / Phantom / Inspire / Spark

Version 2.4.0(June 13, 2018)
- pano mode speed and reliability improvements
- pano mode settings revamp
- when the general setting "Show GPS coordinates" is enabled, you can now edit waypoint GPS coordinates in their settings

Android: Litchi for DJI Mavic / Phantom / Inspire / Spark

Version 4.7.0(June 13, 2018)
- pano mode speed and reliability improvements
- pano mode settings revamp
- fixed bug where changing the app's language would fail on some devices

May 2018 Updates

iOS: Litchi for DJI Mavic / Phantom / Inspire / Spark

Version 2.3.0(May 25, 2018)
- fixed bug where in some cases a waypoint mission could fail to start without showing a reason
- fixed bug where the orbit speed could not be set without being connected to a drone
- fixed bug where having more than 60 waypoints would cause lag
- added new "Save to Panorama Database" pano setting

Android: Litchi for DJI Mavic / Phantom / Inspire / Spark

Version 4.6.1(May 24, 2018)
- fixed bug where some flight modes would fail to start with Spark
- performance improvements
- added new map engine option: Mapbox

Web: Mission Hub

Version 1.2.0(May 24, 2018)
- missions created in Mission Hub are now private by default instead of public

April 2018 Updates

iOS: Litchi for DJI Mavic / Phantom / Inspire / Spark

Version 2.2.0(April 24, 2018)
- added support for Mavic Air
- fixed exposure compensation bug in Shutter/Aperture Priority modes

Android: Litchi for DJI Mavic / Phantom / Inspire / Spark

Version 4.6.0(April 24, 2018)
- added support for Mavic Air
- speed improvements for panoramas shot with Pano mode

March 2018 Updates

iOS: Litchi for DJI Mavic / Phantom / Inspire / Spark

Version 2.1.4(April 5, 2018)
- hotfixed bug with gimbal angles in waypoint missions
Version 2.1.3(April 1, 2018)
- hotfixed bug where interpolate gimbal angles would not always be correctly loaded
Version 2.1.2(March 29, 2018)
- added lock/unlock feature for mission editing; when loading a mission it will be locked for editing by default
- improved support for altitudes above ground level in waypoint mode
- fixed bug where in some cases the POI setting of a waypoint would not save correctly

Android: Litchi for DJI Mavic / Phantom / Inspire / Spark

Version 4.4.2(March 29, 2018)
- added lock/unlock feature for mission editing; when loading a mission it will be locked for editing by default
- improved support for altitudes above ground level in waypoint mode
- fixed bug where in some cases the POI setting of a waypoint would not save correctly

February 2018 Updates

Web: Mission Hub

Version 1.1.9(Feb 13, 2018)
- added support for altitudes relative to ground
- added support for batch editing (using control/command + left click for multiple waypoints selection)
- added new help section for Mission Hub: https://flylitchi.com/help#missionhub
- added support for Visual Mission Planning with Google Earth Pro
- altitudes now have up to 1 decimal of precision
- improved support for CSV import/export
- fixed bug where in some cases the POI setting of a waypoint would not save correctly

Android: Litchi for DJI Mavic / Phantom / Inspire / Spark

Version 4.4.1(Feb 27, 2018)
- fixed crash at startup on devices with intel processors
Version 4.4.0(Feb 08, 2018)
- added RTH/Land button in FPV mode
- added Smart Return to Home general setting
- added support for bluetooth controllers
- misc bug fixes and improvements

January 2018 Updates

iOS: Litchi for DJI Mavic / Phantom / Inspire / Spark

Version 2.1.1(Jan 18, 2018)
- re-enabled Infinity Focus (Mavic Pro only)
Version 2.1.0(Jan 11, 2018)
- added support for x7 camera
- updated to DJI SDK 4.4 which fixes the crash on 32 bit devices

December 2017 Updates

iOS: Litchi for DJI Mavic / Phantom / Inspire / Spark

Version 2.0.0(Dec 22, 2017)
- speed improvements for panoramas shot with Pano mode
- added Auto Pano and Panorama database features (can be used for in-app panorama stitching and sharing), learn more at https://flylitchi.com/help#pano-p3
- known issue in 1.19.0 and 2.0.0: Litchi will crash at startup on older iOS devices (iPhone 5, iPhone 5c, iPad 2, iPad 3, iPad 4 and iPad mini 1) due to a recent update from DJI's software libraries, we are working on restoring support for these devices

November 2017 Updates

iOS: Litchi for DJI Mavic / Phantom / Inspire / Spark

Version 1.19.0(Nov 06, 2017)
- added support for iPhone X
- added RTH/Land button in FPV mode
- added Smart Return to Home general setting
- added support for bluetooth controllers
- added "Find My Aircraft" in general settings
- added a custom function to "Toggle FPV/Main Camera" (Inspire 2)

August 2017 Updates

iOS: Litchi for DJI Mavic / Phantom / Inspire / Spark

Version 1.18.0(Aug 04, 2017)
- added support for Spark: all flight modes are supported except waypoint/orbit at this time (if you are using Spark with the remote controller, you must connect using Wi-Fi between the RC and the mobile device, connecting via USB OTG is not currently supported)
- added Tripod function in FPV mode (for supported drones only: Spark/Mavic Pro/Phantom 4 Adv-Pro/Inspire 2)
- added custom function to "Toggle Tripod Mode"
- added "Gimbal Gesture Control" general setting that lets you enable/disable the scroll movements on the video preview to move the gimbal
- added "Show GEO Warning Zones" general setting that lets you show/hide GEO warning zones on the map
- added a stop button in all flight modes that can be used to stop the current flight (waypoint, orbit, pano, focus, track)
- a warning will now be shown when "Multiple Flight Mode" is disabled in DJI Go

Android: Litchi for DJI Mavic / Phantom / Inspire / Spark

Version 4.1.2(Aug 16, 2017)
- fixed issue where the gimbal would not always rotate smoothly in waypoint missions
Version 4.1.1(Aug 07, 2017)
- bug fixes
Version 4.1.0(Aug 04, 2017)
- added support for Spark: all flight modes are supported except waypoint/orbit at this time (if you are using Spark with the remote controller, you must connect using Wi-Fi between the RC and the mobile device, connecting via USB OTG is not currently supported)
- added Tripod function in FPV mode (for supported drones only: Spark/Mavic Pro/Phantom 4 Adv-Pro/Inspire 2)
- added custom function to "Toggle Tripod Mode"
- added a stop button in all flight modes that can be used to stop the current flight
- a warning will now be shown when "Multiple Flight Mode" is disabled in DJI Go

July 2017 Updates

iOS: Litchi for DJI Mavic / Phantom / Inspire / Spark

Version 1.17.2(Jul 17, 2017)
- added Precision landing and Landing protection settings for Phantom 4
- added support for polygon shaped no fly zones (for china)
- misc improvements and bug fixes
Version 1.17.1(Jul 11, 2017)
- misc improvements and bug fixes
Version 1.17.0(Jul 03, 2017)
- with the latest DJI firmware for Mavic Pro (v01.03.0800 or higher), Phantom 4 Pro (v01.04.0602 or higher), Phantom 4 Advanced (v01.00.0128 or higher), Inspire 2 (v01.01.0010 or higher), Phantom 3 Standard (v1.9.20 or higher), Phantom 3 4K (v1.6.50 or higher), Phantom 3 Advanced/Pro (v1.11.20 or higher), Phantom 4 (v02.00.0106 or higher), users in China are required to activate Litchi by logging into their DJI account at least once every three months, this can now be done within Litchi. Outside of China, Litchi will automatically activate the application without requiring the user to log in within Litchi or DJI Go
- added support for Phantom 4 Advanced
- added "Over Exposure Warning" general camera setting
- added "Enhance Display for D-Log Filter" general camera setting
- fixed issue where the RC shutter button would not always use the selected capture mode
- misc improvements and bug fixes

Android: Litchi for DJI Mavic / Phantom / Inspire / Spark

Version 4.0.2(Jul 17, 2017)
- added Precision landing and Landing protection settings for Phantom 4
- added "Send Feedback" button in the general settings
- misc improvements and bug fixes
Version 4.0.1(Jul 11, 2017)
- misc improvements and bug fixes
Version 4.0.0(Jul 05, 2017)
- with the latest DJI firmware for Mavic Pro (v01.03.0800 or higher), Phantom 4 Pro (v01.04.0602 or higher), Phantom 4 Advanced (v01.00.0128 or higher), Inspire 2 (v01.01.0010 or higher), Phantom 3 Standard (v1.9.20 or higher), Phantom 3 4K (v1.6.50 or higher), Phantom 3 Advanced/Pro (v1.11.20 or higher), Phantom 4 (v02.00.0106 or higher), users in China are required to activate Litchi by logging into their DJI account at least once every three months, this can now be done within Litchi. Outside of China, Litchi will automatically activate the application without requiring the user to log in within Litchi or DJI Go
- added support for Phantom 4 Advanced
- added AutoFocus Continuous mode (AFC) for Mavic Pro, Phantom 4 Pro and X4S
- fixed issue where the RC shutter button would not always use the selected capture mode
- fixed licensing issue
- misc improvements and bug fixes

May 2017 Updates

iOS: Litchi for DJI Mavic / Phantom / Inspire / Spark

Version 1.16.2(May 24, 2017)
- added "Share" button in the Facebook live settings giving you the ability to share your live stream on a friend's timeline or in a Facebook group
- misc improvements and bug fixes
Version 1.16.1(May 19, 2017)
- upgraded Airdata UAV's free subscription offer from Gold to Pro plan
Version 1.16.0(May 16, 2017)
- added Facebook live streaming feature (tap on the share icon at the top right corner of the video preview to start it)
- added "Cache Videos" setting. When enabled, recording videos with the drone will also cause Litchi to save the video to the "Litchi Video Cache" album in the Photos app
- added "Cache Photos" setting. When enabled, photos you take will be saved to the 'Litchi Photo Cache' album (in the Photos app). Photo Caching does not work when the image format is set to RAW or when using the Interval capture mode. Photo Caching does not work during Waypoint, Pano and Track sessions
- added "Photo Preview" setting. Requires "Cache Photos" setting to be enabled. When enabled, after taking a photo a preview will be shown along with a share button providing an easy way to share the photo to Facebook
- added AutoFocus Continuous mode (AFC) for Mavic Pro, Phantom 4 Pro and X4S
- added uplink/downlink signal information to the VR mode display
- faster panoramas with Mavic Pro
- reliability improvements for Pano mode
- references to HealthyDrones replaced with its new name, Airdata UAV
- fixed issue with M600/M600 Pro RC switch not being recognized correctly
- misc improvements and bug fixes

Android: Litchi for DJI Mavic / Phantom / Inspire / Spark

Version 3.10.10(May 24, 2017)
- added "Share" button in the Facebook live settings giving you the ability to share your live stream on a friend's timeline or in a Facebook group
- fixed issue where streaming with Facebook live using the Public or Friends privacy setting would instead appear as "Only me"
- fixed issue where for some devices the Facebook Page profiles would not display correctly after a tap on the user's profile picture in the Facebook Live settings
Version 3.10.9(May 19, 2017)
- upgraded Airdata UAV's free subscription offer from Gold to Pro plan
Version 3.10.8(May 16, 2017)
- added Facebook live streaming feature (tap on the share icon at the top right corner of the video preview to start it)
- added uplink/downlink signal information to the VR mode display
- added autoland button in FPV mode
- faster panoramas with Mavic Pro
- reliability improvements for Pano mode
- references to HealthyDrones replaced with its new name, Airdata UAV
- fixed issue with M600/M600 Pro RC switch not being recognized correctly
- misc improvements and bug fixes

April 2017 Updates

iOS: Litchi for DJI Mavic / Phantom / Inspire / Spark

Version 1.15.9(Apr 07, 2017)
- due to a bug in the DJI firmware, Focus, Track and VR with Immersive/Joystick Head Tracking modes are no longer usable with the following drone models and firmware versions: Mavic Pro (v01.03.0550 and v01.03.0500), Inspire 2 (v01.0.0240) and Phantom 4 Pro (v01.03.0418). If you are using one of these firmware versions and wish to continue using the affected flight modes, either downgrade to a previous firmware version using the DJI Assistant 2 PC/Mac app or wait for DJI to release a new firmware that will fix this bug

Android: Litchi for DJI Mavic / Phantom / Inspire / Spark

Version 3.10.7(Apr 06, 2017)
- due to a bug in the DJI firmware, Follow, Focus, Track and VR with Immersive/Joystick Head Tracking modes are no longer usable with the following drone models and firmware versions: Mavic Pro (v01.03.0550 and v01.03.0500), Inspire 2 (v01.0.0240) and Phantom 4 Pro (v01.03.0418). If you are using one of these firmware versions and wish to continue using the affected flight modes, either downgrade to a previous firmware version using the DJI Assistant 2 PC/Mac app or wait for DJI to release a new firmware that will fix this bug

March 2017 Updates

iOS: Litchi for DJI Mavic / Phantom / Inspire / Spark

Version 1.15.8(Mar 21, 2017)
- fixed hardware decoding bug
- fixed issue where the battery serial would not correctly update in the flight logs when changing the battery
- due to a bug in the DJI firmware, Focus, Track and VR with Immersive/Joystick Head Tracking modes are no longer usable with the following drone models and firmware versions: Mavic Pro (v01.03.0500), Inspire 2 (v01.0.0240) and Phantom 4 Pro (v01.03.0418). If you are using one of these firmware versions and wish to continue using the affected flight modes, either downgrade to a previous firmware version using the DJI Assistant 2 PC/Mac app or wait for DJI to release a new firmware that will fix this bug
Version 1.15.7(Mar, 2017)
- added shutter and aperture priority exposure modes
- long press anywhere on the video preview to set Focus to Infinity for Mavic Pro
- added custom function "Focus to Infinity" for Mavic Pro
- added Burst shot x10/x14 capture modes for P4 Pro / Inspire 2
- added Inspire 2 SSD settings
- added FPV Camera support for Inspire 2
- bug fixes for Phantom 3 4K

Android: Litchi for DJI Mavic / Phantom / Inspire / Spark

Version 3.10.6(Mar 20, 2017)
- due to a bug in the DJI firmware, Follow, Focus, Track and VR with Immersive/Joystick Head Tracking modes are no longer usable with the following drone models and firmware versions: Mavic Pro (v01.03.0500), Inspire 2 (v01.0.0240) and Phantom 4 Pro (v01.03.0418). If you are using one of these firmware versions and wish to continue using the affected flight modes, either downgrade to a previous firmware version using the DJI Assistant 2 PC/Mac app or wait for DJI to release a new firmware that will fix this bug

February 2017 Updates

iOS: Litchi for DJI Mavic / Phantom / Inspire / Spark

Version 1.15.6(Feb 13, 2017)
- fixed rare issue with mavic pro battery not updating correctly
Version 1.15.5(Feb 04, 2017)
- added new "relative to ground" mode to set waypoint altitudes in the batch waypoint editor
- panorama bug fix for Mavic Pro

Android: Litchi for DJI Mavic / Phantom / Inspire / Spark

Version 3.10.5(Feb 25, 2017)
- fixed an issue with Mavic Pro where tap to focus would fail
- fixed a Mavic Pro issue where it is not possible to control the gimbal manually when the app has control in waypoint mode (focus poi/interpolate)
Version 3.10.4(Feb 14, 2017)
- when uploading a waypoint mission, a progress window will now be shown
Version 3.10.3(Feb 03, 2017)
- follow me fix with Mavic Pro & P4 Pro
- panorama bug fix for Mavic Pro
- misc improvements and bug fixes

January 2017 Updates

iOS: Litchi for DJI Mavic / Phantom / Inspire / Spark

Version 1.15.4(Jan 27, 2017)
- a visual effect will now be shown when the drone is taking a photo
- misc improvements and bug fixes
Version 1.15.3(Jan 24, 2017)
- added support for Inspire 2
- misc improvements and bug fixes
Version 1.15.2(Jan 17, 2017)
- fixed rare crash at startup on some devices
- some diagnostic errors/warnings can now be closed

Android: Litchi for DJI Mavic / Phantom / Inspire / Spark

Version 3.10.2(Jan 26, 2017)
- added support for Inspire 2
- a visual effect will now be shown when the drone is taking a photo
- misc improvements and bug fixes

December 2016 Updates

iOS: Litchi for DJI Mavic / Phantom / Inspire / Spark

Version 1.15.1(Dec 22, 2016)
- added "Active Collision Avoidance", "Landing Protection", "Precision Landing", "Frequency Band", "Lightbridge 2 Channel Switch" settings
- added "JPEG Quality", "Video Caption", "Front LEDs Auto Turn Off", "Auto AE Unlock", "AF Focus Assistant" and "Video Coding" settings
- fixed custom buttons C1/C2 conflict
Version 1.15.0(Dec 19, 2016)
- added support for Phantom 4 Pro
- misc bug fixes

Android: Litchi for DJI Mavic / Phantom / Inspire / Spark

Version 3.10.1(Dec 28, 2016)
- fixed crash in the settings with Phantom 4
Version 3.10.0(Dec 22, 2016)
- added support for Phantom 4 Pro
- added new "relative to ground" mode to set waypoint altitudes in the batch waypoint editor
- added "Active Collision Avoidance", "Landing Protection", "Precision Landing", "Frequency Band" settings

November 2016 Updates

iOS: Litchi for DJI Mavic / Phantom / Inspire / Spark

Version 1.14.3(Nov 22, 2016)
- pano mode bug fix
Version 1.14.2(Nov 17, 2016)
- the "Center Autofocus" custom function can now be used in VR mode
- fixed issue where in some cases a video decoder encryption error would incorrectly be shown
- fixed issue where the battery would sometimes fail to connect
Version 1.14.0 - 1.14.1(Nov 08, 2016)
- added support for Mavic Pro
- added "Ocusync Preview Quality" and "Ocusync Transmission Channel" general settings (Mavic Pro only)
- added support for Landing confirmation
- added "Full HD Stream" and "Portrait Mode" camera settings (Mavic Pro only)
- added "5D button" key bindings in general settings (Mavic Pro only)
- added new custom functions for "Digital Zoom In/Out", "AE Lock/Unlock" and "Toggle Portrait Mode"
- added "Peak Focus Threshold" general camera setting
- fixed issues with optical zoom

Android: Litchi for DJI Mavic / Phantom / Inspire / Spark

Version 3.9.2(Nov 29, 2016)
- fixed bug where optical zoom with Z3 camera would not work
- fixed bug where the phone camera's orientation would sometimes be incorrect in VR mode
Version 3.9.1(Nov 25, 2016)
- misc bug fixes
Version 3.9.0(Nov 24, 2016)
- added support for Mavic Pro
- Pano mode revamp and optimizations
- added support for Landing confirmation
- added "Full HD Stream" and "Portrait Mode" camera settings (Mavic Pro only)
- added "5D button" bindings (Mavic Pro only)
- added new custom functions for "Digital Zoom In/Out", "AE Lock/Unlock" , "Center Autofocus" and "Toggle Portrait Mode"
- setting the metering/autofocus is now done with a tap on the video preview
- added support for optical zoom (C2 + left wheel)

October 2016 Updates

iOS: Litchi for DJI Phantom/Inspire

Version 1.13.1(Oct 31, 2016)
- added "Capture Strategy" setting in Pano mode, switch between "Column by Column" and "Row by Row"
- added "Mode" setting in Pano mode, switch between "Aircraft Rotation" and "Gimbal Rotation" (Inspire 1/M100/M600/A3 only)
- added "Nadirs" setting in Pano mode, allows selecting the number of Nadirs Litchi will take
- added "Width" setting in Pano mode, which lets you shoot non spherical panoramas
- added "Top Row Angle" setting in Pano mode, allows you to set the top row's pitch angle from 0 to +30°
- added GEO restricted flight zones to the map
- added setting to enable/disable GEO system, when disabled the app will use the previous NoFlyZone system (not up to date)
- added more warning messages that will display when a problem is detected
Version 1.13.0(Oct 24, 2016)
- Pano mode revamp and optimizations
- setting the exposure metering is now done with a tap on the video preview
- triggering autofocus is now done with a tap on the video preview, switch between autofocus and exposure metering functions using the button at the top left corner of the video preview (X5/Z3/Mavic only)
- added setting to show GPS coordinates
- added "Center AutoFocus" custom function to trigger AutoFocus at the center
- optical zoom can now be triggered using C2+left RC wheel
- optical zoom bug fix
- many UI improvements and bug fixes
Version 1.12.4(Oct 13, 2016)
- fixed screen recording crash on iOS 9
Version 1.12.3(Oct 12, 2016)
- fixed issue where sometimes video recording would restart mid-flight with auto record enabled
Version 1.12.2(Oct 08, 2016)
- added optical zoom support (pinch to zoom on video preview) for Z3 and X5 zoom lens
- added autofocus support for Z3 camera
Version 1.12.1(Oct 06, 2016)
- added lightbridge 2 setting to switch between LB/EXT video sources
- fixed korean translation issue
Version 1.12.0(Oct 05, 2016)
- added Litchi Vue support (stream the video feed to a nearby iOS device running the Litchi Vueapp)
- added initial support for z3 camera
- fixed issue with map zoom

Android: Litchi for DJI Phantom/Inspire

Version 3.8.0(Oct 18, 2016)
- added batch edit tool in waypoint mode
- waypoint altitudes are now shown above each waypoint
- remaining sdcard space is now shown in the settings
- added terrain map type
- misc bug fixes

September 2016 Updates

iOS: Litchi for DJI Phantom/Inspire

Version 1.11.0(Sep 19, 2016)
- added batch edit tool in waypoint mode
- waypoint missions now show distance info between waypoints
- remaining sdcard space is now shown in the settings
- added Use Amap Imagery general setting (for China maps)
- added terrain map type
- the app now uses new database servers for missions saved to the cloud, be sure to update the app to continue using Mission Hub's features

Android: Litchi for DJI Phantom/Inspire

Version 3.7.0(Sep 19, 2016)
- the app now uses new database servers for missions saved to the cloud, be sure to update the app to continue using Mission Hub's features

August 2016 Updates

iOS: Litchi for DJI Phantom/Inspire

Version 1.10.2(Aug 11, 2016)
- long press to autofocus will now also change the focus mode if not already on auto (X5 & X5R)
- fixed autofocus and spot metering in photo mode 4:3
- fixed issue with histogram in photo mode 4:3
- updated translations
Version 1.10.1(Aug 03, 2016)
- added ability to move the gimbal using touch/drag on the video preview
- updated translations
- a broken SDcard icon will now be shown when there is a problem with the sdcard
- max number of missions increased from 100 to 1000
- fixed no sound when taking photos with the Interval capture mode
- in flight logs, the channel will now show correct values for Auto
- missions with empty names are no longer allowed

Android: Litchi for DJI Phantom/Inspire

Version 3.6.8(Aug 12, 2016)
- long press to autofocus will now also change the focus mode if not already on auto (X5 & X5R)
Version 3.6.7(Aug 11, 2016)
- added how to connect help at app startup
Version 3.6.6(Aug 09, 2016)
- added battery info/settings panel, tap on battery icon to show it
- added video recording time
- replaced Gimbal FPV mode setting by Gimbal Mode setting
- max number of missions increased from 100 to 1000
- updated translations
- fixed autofocus and spot metering in photo mode 4:3
- fixed issue with histogram in photo mode 4:3

July 2016 Updates

iOS: Litchi for DJI Phantom/Inspire

Version 1.10.0(Jul 15, 2016)
- added support for the following languages: German, Italian, French, Russian, Chinese Simplified, Chinese Traditional, Spanish, Japanese, Czech, Dutch, Danish, Greek, Hungarian, Korean, Indonesian, Portuguese (Brazil), Portuguese (Portugal), Polish, Vietnamese, Finnish, Swedish, Turkish, Romanian
- added language general setting
- added battery info/settings, tap on battery icon to show the settings
- added remaining flight time indicator
- added digital zoom for Phantom 4
- added Double Output (HDMI) general setting
- fixed bug where the username would show as (null) when logged in via Facebook

Android: Litchi for DJI Phantom/Inspire

Version 3.6.5(Jul 13, 2016)
- updated translations
Version 3.6.4(Jul 08, 2016)
- updated translations

June 2016 Updates

iOS: Litchi for DJI Phantom/Inspire

Version 1.9.2(Jun 30, 2016)
- fixed issue where the top bar status would allow to cancel a Landing caused by reaching the critical battery level
Version 1.9.1(Jun 29, 2016)
- added ability to set different speeds at each waypoint (only effective when the aircraft is in range of the RC)
- added vision positioning general setting
- when the aircraft is in Go Home/Landing modes, you can now tap on the top status bar to cancel the RTH/Landing
- added ability to set exposure spot using single tap on video preview, when using spot metering mode
- when starting the app, the last flight mode that was used will be selected
- added load/save to Orbit mode
- added long press bindings for C1/C2
- added custom functions 'Toggle VR Immersive' and 'Toggle VR Joystick'
- added ability to unlock map to have it rotate with the device heading
- misc bug fixes
Version 1.9.0(Jun 17, 2016)
- added VR mode
- added FPV mode with auto takeoff/land, course lock and home lock functions
- added custom function to toggle the iphone camera in VR mode
- added "Show Home Orientation" general setting, when enabled shows a line between home point and aircraft on the map
- added gimbal work mode general setting
- added gimbal FOV indicator for inspire 1 series
- fixed focus mode with aircraft rotation off for Inspire 1 series
Version 1.8.0(Jun 07, 2016)
- added voice feedback settings
- added compass calibration in settings
- added maximum altitude general setting
- misc improvements and bug fixes

Android: Litchi for DJI Phantom/Inspire

Version 3.6.3(Jul 01, 2016)
- updated translations
Version 3.6.2(Jun 29, 2016)
- added ability to set different speeds at each waypoint (only effective when the aircraft is in range of the RC)
- added vision positioning general setting
- when the aircraft is in Go Home/Landing modes, you can now tap on the top status bar to cancel the RTH/Landing
- added ability to set exposure spot using single tap on video preview, when using spot metering mode
- for X5 cameras, focus is now done with a long press
- fixed bug with insert waypoint feature changing the altitude for other waypoints
- removed "Minimum/Maximum selectable altitude" settings which now default to -200m (min) and 500m (max)
- fixed bug where a space at the end of the email would cause failed logins
Version 3.6.1(Jun 22, 2016)
- misc bug fixes
Version 3.6.0(Jun 22, 2016)
- added 'Aircraft Head Tracking' in VR mode to control the aircraft yaw with your head
- added home indicator in VR mode
- added recording indicator in VR mode
- added 'Show Home Orientation' general setting
- added 'Mobile Camera (VR)' custom function with which you can toggle your mobile device's camera in VR mode
- added 'Toggle VR Immersive' and 'Toggle VR Joystick' custom functions
- added 1080p 120 fps recording resolution for Phantom 4
- fixed inspire 1 yaw head tracking vr bug
Version 3.5.0(Jun 06, 2016)
- added in-app exposure settings (tap on exposure info panel at the top of the video preview to show the settings)
- added voice instructions for compass calibration
- minor tracking improvements for P3S when the camera is in photo mode and for the Nvidia Shield tablet in both camera modes
- misc improvements and bug fixes

May 2016 Updates

iOS: Litchi for DJI Phantom/Inspire

Version 1.7.0(May 20, 2016)
- added ability to start one month free trial for Airdata UAV's HD 360 Gold subscription (exclusive to Litchi), refer to https://flylitchi.com/airdata for more info
- improvements to automatic gimbal control in waypoint mode
- added object avoidance info (distance in meters) and sounds for Phantom 4
- added RC Signal Lost general aircraft setting (only affects manual flying)
- added Gimbal Pitch Extension general aircraft setting
- added front LEDs general setting (also added as custom function for C1/C2)
- added collision avoidance general setting for Phantom 4
- in Focus and Track modes for Inspire type aircrafts, the gimbal yaw will no longer be controlled when aircraft rotation is set to auto

Android: Litchi for DJI Phantom/Inspire

Version 3.4.0(May 20, 2016)
- added ability to start one month free trial for Airdata UAV's HD 360 Gold subscription (exclusive to Litchi), refer to https://flylitchi.com/airdata for more info
- improvements to automatic gimbal control in waypoint mode
- added object avoidance info (distance in meters) and sounds for Phantom 4
- added RC Signal Lost general aircraft setting (only affects manual flying)
- added Gimbal Pitch Extension general aircraft setting
- added front LEDs general setting (also added as custom function for C1/C2)
- added collision avoidance general setting for Phantom 4
- in Focus and Track modes for Inspire type aircrafts, the gimbal yaw will no longer be controlled when aircraft rotation is set to auto

April 2016 Updates

iOS: Litchi for DJI Phantom/Inspire

Version 1.6.0(Apr 26, 2016)
- you can now activate Follow in Track mode. When using Track's Follow feature always be ready to use the RC switch to regain control
- smoother joystick controls in Track and Focus mode
- added histogram in camera settings
- screen recorder should be more reliable
- gimbal roll can now be adjusted using C2 + right wheel
Version 1.5.0(Apr 05, 2016)
- added support for Phantom 4
- added new Track mode which uses computer vision to track a selected object
- added new Focus mode which uses GPS to focus on a subject
- added all camera settings and exposure details panel
- added support for Auto-Focus on tap (X5 and X5R only)
- the C1 RC button setting is now enabled again
- fixed hardware decoding setting not always applying correctly
- fixed issue with waypoint mode finish action "Back to 1"

Android: Litchi for DJI Phantom/Inspire

Version 3.3.1(Apr 27, 2016)
- fixed rare crash at startup on galaxy s6 devices
Version 3.3.0(Apr 26, 2016)
- added new Track mode which uses computer vision to track a selected object. When using Track's Follow feature always be ready to use the RC switch to regain control
- Focus mode is now included in the base app, the base price has been adjusted accordingly
- smoother joystick controls in Track and Focus mode
- added histogram in general camera settings
- added Focus on long press for X5 and X5R cameras
- added Hue camera setting
- misc bug fixes
Version 3.2.1(Apr 01, 2016)
- hotfixed pano mode with gimbal rotations for Inspire 1
Version 3.2.0(Mar 31, 2016)
- added support for Phantom 4 (autonomous flights require P mode, switch to S or A to regain control)
- improvements to Focus mode so movements should be less affected by wind
- added AEB capture mode settings
- panoramas taken in Pano mode with a P3/P4 should be more stable and less affected by wind
- fixed bug where exposure info wasn't correctly updated in manual mode

March 2016 Updates

iOS: Litchi for DJI Phantom/Inspire

Version 1.4.0(Mar 09, 2016)
- added panorama mode
- added grid lines camera setting

Android: Litchi for DJI Phantom/Inspire

Version 3.1.0(Mar 21, 2016)
- improvements to panorama mode to make it more reliable

February 2016 Updates

iOS: Litchi for DJI Phantom/Inspire

Version 1.3.1(Feb 13, 2016)
- fix iPad Pro crash
Version 1.3.0(Feb 12, 2016)
- added Orbit flight mode
- misc improvements and bug fixes

Android: Litchi for DJI Phantom/Inspire

Version 3.0.4(Feb 29, 2016)
- improved POI transitions in Focus POI waypoint missions
- fixed downlink signal bars not showing for some users
- misc bug fixes
Version 3.0.3(Feb 16, 2016)
- fixed crash on some devices
Version 3.0.2(Feb 15, 2016)
- fixed compass error not removing itself after successful calibration
- fixed a bug where in some cases no errors would be shown if the app failed to register with the DJI servers
- fixed a bug where the P3 standard signal quality would not be stable
- fixed wrong no fly zone warnings
Version 3.0.1(Feb 12, 2016)
- added support for P3 Standard, P3 4K, Inspire 1 Pro/Raw
- removed P2 vision and P2 vision + support
- added aircraft model auto detection
- added new camera shooting modes (HDR and AEB)
- added new mission finish action Reverse
- added ability to change the cruising speed while a mission is in progress
- removed aircraft type and video decoder settings
- misc improvements and bug fixes

Источник: [https://torrent-igruha.org/3551-portal.html]
Xbox & Windows 10". Xbox.com. Retrieved 2019-06-10.
  • ^"Archived copy". Archived from the original on 2020-03-02. Retrieved 2020-03-02.CS1 maint: archived copy as title (link)
  • ^"Archived copy". Archived from the original on 2020-09-20, 21 Flying Images 2.0 crack serial keygen. Retrieved 2020-12-18.CS1 maint: archived copy as title (link)
  • ^"Archived copy". Archived from the original on 2020-11-27. Retrieved 2020-12-18.CS1 maint: archived copy as title (link)
  • ^Fastie, Will (January 1983). "Flight Of The 5150: The PC Takes Off". PC Magazine. p. 303. Archived from the original on 31 December 2013. Retrieved 21 October 2013.
  • ^Malloy, Rich (December 1983). "Reviewer's Notebook". BYTE. p. 282. Retrieved 20 October 2013.
  • ^Miastkowski, Stan (March 1984). "Microsoft Flight Simulator". BYTE. p. 224. Retrieved 22 October 2013.
  • ^Aarons, Dick (1984-10-02). "A Perfect Flight". PC Magazine. p. 269. Archived from the original on 2014-01-01. Retrieved 25 October 2013.
  • ^Florance, David (December 1984). "Microsoft Flight Simulator for PC & PCjr". Compute! (review). p. 142. Retrieved 30 October 2013.
  • ^Lesser, Hartley; Lesser, Patricia; Lesser, Kirk (February 1989). "The Role of Computers". Dragon (142): 42–51.
  • ^Trimble, Timothy L. (January 1994). "The Friendly Skies Of Flight Simulator 5". Computer Gaming World. pp. 108–109. Archived from the original on 2019-12-09. Retrieved 2017-11-08.
  • ^Jeff Lackey, "Microsoft Flight Simulator Review"Archived 2012-10-06 at the Wayback Machine, 21 Flying Images 2.0 crack serial keygen, GameSpot, 21 Oct 2012
  • ^"Computer Games: Best-Selling Flight Simulator". Guinness World Records 2001. Guinness. 2000. p. 121. ISBN .
  • ^Moses, Asher (2009-03-12). "Matt's on a different plane . and it's surreal". The Sydney Morning Herald. Archived from the original on 2012-01-15. Retrieved 12 May 2012.
  • External links[edit]

    Источник: [https://torrent-igruha.org/3551-portal.html]
    Purchase and Preparation
    1.How do I purchase DJI Terra?

    DJI Terra Agriculture is available to order at the DJI online store.

    DJI Terra Pro, DJI Terra Electricity online version and DJI Terra Cluster offline version are available to order through DJI dealers.

    You can also get a license for DJI Terra Agriculture when purchasing MG-1S Advanced, MG-1P or T series agricultural drones.

    2.For how long will my DJI Terra license be effective?

    Your license comes into effect starting the day the device is bound to DJI Terra.
    DJI Terra Agriculture 1 year
    DJI Terra Pro 1 year
    DJI Terra Pro Permanent
    DJI Terra Electricity 1 year
    DJI Terra Cluster Permanent

    3.What do I need to start using DJI Terra?

    1. A Phantom 4 Series drone that supports DJI Terra, several batteries;
    2. A laptop, a microSD card and a card reader;
    3. A compatible cable (a USB-to-USB cable for Phantom 4, Phantom 4 Pro, Phantom 4 Advanced, a Micro-USB cable for Phantom 4 Pro + V2.0, a USB-C cable for Phantom 4 RTK).

    4.What are the computer system requirements for 2D and 3D reconstruction with DJI Terra?

    A Windows 7 or above (64 bits) system is required when using the DJI Terra.
    Minimum hardware configuration: 16GB RAM and a NVIDIA graphics card with at least 21 Flying Images 2.0 crack serial keygen VRAM (must have a compute capability of 3.0 or above).
    Recommended hardware configuration: at least 32GB RAM and at least a NVIDIA 1050 Ti.
    With these configuration requirements met, every additional 10 GB of RAM will be able to process 4000 additional 4K images. The higher the system configurations, the larger the number of images that can be processed and the faster the reconstructions. The results from the models generated will not be affected by different hardware configurations.

    5.Which aircraft are supported by DJI Terra?

    Phantom 4 RTK (Remote Controller), Phantom 4 Pro V2.0, Phantom 4 Pro+ V2.0, Phantom 4 Pro, Phantom 4 Advanced and Phantom 4. The Phantom 4 does not support 2D Real-time Mapping.

    6.Can I still use the paid features of DJI Terra without an internet connection?

    Yes.
    For the offline version, once installed, all paid features operate without 21 Flying Images 2.0 crack serial keygen internet connection.
    For the online version, you must have an internet connection to login, however, you can continue to DJI Terra's paid features offline without logging in again for up to 3 days.

    7.Why am I unable to switch the remote controller to PC Mode?

    There are three possible reasons cause this problem:
    (1)Drivers not installed. Connect the remote controller to DJI Terra via a USB cable. If a yellow exclamation point appears on the Device Manager’s serial port connection, you will need to install a driver; right click to install the driver.
    (2)The Phantom 4 Pro+ remote controller (with display) fails to connect with DJI Terra.
    (3)Your remote controller has an HDMI module. Only remote controllers without an HDMI module, with a USB port and a Micro USB port, can be switched to PC mode.
    *Phantom 4 RTK and Phantom 4 Pro V2.0 series aircraft need not to be switched to remote controller mode.

    8.Can I unbind devices from DJI Terra licenses?

    You can unbind your DJI Terra Agriculture, Pro, Electricity and Cluster licenses(Except Agras-gift Agriculture license). To unbind, please contact DJI Support. The 1-device licenses can be unbound once in each natural year. 3-device licenses can be unbound twice in each natural year, 21 Flying Images 2.0 crack serial keygen. Once processed, all devices registered under the license will be unbound.

    9.What is the one-year free update period?

    It is the one-year period from the first date of binding any permanent package after purchase, during which you can update to any version released in that period for free and use all functions included in the package.

    10.My software has gone into the paid update period but I have not paid any upgrading and maintenance fee. It has been a few years and I would now like to upgrade it to the latest version. Do I need to pay the upgrading and maintenance fees for the previous years?

    Yes.

    11.My software has gone into the paid update period but I have not paid any upgrading and maintenance fee. I have since downloaded a new version released during the paid update period. Will I be able to use it?

    The paid functions will not be available, but you can still use the basic functions.

    12.Will unbinding the software change its first binding date?

    It will not.

    13.I have two types of licenses: A and B (Pro and Electricity versions, for example). The update validity period is the same on both of them.
    The Electricity version has gone into the paid update period but no upgrade and maintenance fee has been paid; the Pro version has also gone into the paid update period but its upgrade and maintenance fee has been paid.
    Will I be able to use the functions on the Electricity version?

    If you have downloaded and updated to a version released during the paid update period, you can use the functions on the Pro version, but not those on the Electricity version.

    14.Can I replace the hardware of my device after the offline version is bound to it?

    No, the license is bound to the device's hardware and therefore replacing hardware would invalidate the license.

    15.What features are restricted in the offline version?

    The following online features are not available in Offline Mode:
    - Unlocking GEO Zones
    - Map loading and location searching
    - Without logging into a DJI account, some flight control functions in DJI Terra are restricted

    Flight and Aerial Photography
    1.What is the difference between Waypoints Mission, Mapping Mission, Oblique Mission, Corridor Mission and Detailed Inspection Mission?

    Waypoints Mission: plan a flight route and capture photos or videos at waypoints along the route.
    Mapping Mission: collect images of an area to reconstruct a 2D model.
    Oblique Mission: collect images of an area from multiple camera angles to reconstruct a 3D model.
    Corridor Mission: collect images of a corridor (e.g. rivers, railroads) to reconstruct a 2D model.
    Detailed Inspection Mission: Set target points on a reconstructed model and a flight route will be automatically generated, allowing the aircraft to capture photos at these target points.

    2.Why are there 5 flight routes when I plan an Oblique Mission in DJI Terra?

    DJI Terra’s Oblique Mission uses 5 flight routes to capture the same amount of data as using 5 cameras simultaneously on a drone. The 5 flight routes correspond to the 5 camera headings – downward, 21 Flying Images 2.0 crack serial keygen, forward, backward, leftward, and rightward.

    3.How do I plan flight routes when there is no internet connection and the map cannot be loaded?

    If 21 Flying Images 2.0 crack serial keygen have access to a mobile device that has an internet connection (such as a cellphone), you can turn on the hotspot so that the laptop can be connected to the internet.
    If the site where you are operating has no internet signal, you can pre-plan the flight route while you are indoors and have an internet connection, or manually fly the drone around the area to be mapped to set boundaries points to plan flight routes.

    4.What is Ground Sample Distance (GSD)?

    In photogrammetry and remote sensing, ground sample distance (GSD) in an aerial digital photo (such as an orthophoto) of the ground is the actual distance on the ground captured as represented by pixels. The unit is cm/pixel.

    5.In the Mapping Mission page, what does Mission Relative Height in Advanced Settings mean? How is it different from Mission Altitude in Basic Settings?

    Mission Relative Height in Advanced Settings is the height of the takeoff point relative to the area being mapped.
    Mission Altitude is the height of the drone relative to the area being mapped, which is also how ground sample distance (GSD) is calculated.

    6.When do I have to adjust the Mission Relative Height in Advanced Settings?

    When there is a large difference between the elevation of the takeoff location and the elevation of the area being mapped, you can adjust the Mission Relative Height in Advanced Settings to ensure that the Mission Altitude is determined considering the elevation of the area being mapped.
    Please see the attached illustration: If the drone takes off from a 50 m building marked H1 in the illustration, 21 Flying Images 2.0 crack serial keygen, the area being mapped is marked A, and the expected altitude for aerial data collection is 100 m, 21 Flying Images 2.0 crack serial keygen, you can set the Mission Altitude in Basic Settings to 100 m, and Mission Relative Height in Advanced Settings to 50 m.
    Similarly, if the drone takes off from H2 to map area B, which is a hill with an 21 Flying Images 2.0 crack serial keygen of 40 m, and the expected altitude for aerial data collection is 60 m, then set Mission Altitude to be 60m, and Mission Relative Height to be -40 m.

    7.What should I do to ensure accuracy 21 Flying Images 2.0 crack serial keygen my missions when collecting data with the Phantom 4 RTK?

    1) Conduct your missions in clear weather conditions with high visibility.
    2) Check the images and videos for brightness and clarity immediately after your mission.
    3) During a surveying mission, avoid areas with strong electromagnetic interference or obstructions to ensure the accuracy of the attitude algorithm of the Phantom 4 RTK. Also make sure that the remote controller is properly linked to the aircraft.
    4) Ensure there is enough forward and side overlap. It is recommended to have a forward overlap rate of 80% and a side overlap rate of 70%. Overlap rates can be adjusted depending on the terrain.

    8.When should I adjust the overlap rates based on the terrain?

    It is recommended to have a forward overlap rate of 80% and a side overlap rate of 70%, which should meet the requirements for most application scenarios. The overlap rate can be increased when the area being mapped has a large difference in elevation to ensure the highest point mapped has enough overlap. When the area mapped is relatively uniform in elevation, the overlap rate can be adjusted lower to reduce the amount of data that needs to be processed, making the mapping mission more efficient. However, it is recommended to keep the forward overlap at a minimum of 65% and side overlap at a minimum of 60%.

    9.When I connect DJI Terra to Phantom 4 RTK, the app tells me that I cannot take off because the RTK signal is too weak. What should I do?

    It could be that you are operating somewhere with a lot of signal interference or obstructions, which affects the strength of the RTK signal. Try turning off the RTK module and take off manually with the GNSS positioning. Once the drone reaches a height where there is less interference, 21 Flying Images 2.0 crack serial keygen, you can turn on the RTK module and connect to DJI Terra to conduct your flight missions.

    10.Which aircraft support Real-time 3D mapping?

    Phantom 4 RTK (Remote Controller), Phantom 4 Pro V2.0, Phantom 4 Pro + V2.0. Note: models may be of poor quality be unavailable in environments without RTK signals.

    11.Can I plan flight routes for Waypoints Missions or Detailed Inspection Missions based on real-time 3D models?

    Yes.

    Detailed Inspection
    1.What models of aircraft are supported by detailed inspection flight path planning?

    Phantom 4 RTK, Matrice 300 RTK

    2.Can third-party point cloud files be imported into DJI Terra?

    Yes, LAS point cloud files can be imported.

    3.Can a third-party LAS point cloud file be imported if it does not contain a coordinate system?

    Yes. You should set the coordinate system when you first import the file. If the file uses an arbitrary coordinate system, you need to correct it using third-party point cloud correction software.

    4.Can detailed inspection missions be conducted if the aircraft is flown at mission relative altitude?

    No, IDM Serial key 2021 crack serial keygen aircraft needs to be flown at absolute altitude.

    5.What are the important things to take note of when planning or executing a detailed inspection mission?

    1. Make sure the RTK data sources are consistent when planning or executing a flight path;
    2. Flight paths can only be executed when the RTK is in FIX status. During execution, you may set the first waypoint as the hovering inspection point. The mission must be stopped if the location of the inspection point is incorrect.

    Building Reconstruction Models
    1.Real-time reconstruction did 21 Flying Images 2.0 crack serial keygen generate map, or only generated some of the early map.

    First make sure if the number of images transmitted differ significantly from the number of images shot. If they do not, you may check the log to see if a “relocalization fail” message has appeared. If so, you need to increase the mission altitude as necessary to enhance the overlap rate.

    2.What are the Field, Urban, and Fruit Tree Scenarios in 2D Map?

    The Field Scenario is designed to capture data from 21 Flying Images 2.0 crack serial keygen relatively flat land, for example rice or wheat fields.
    The Urban Scenario is designed for areas with buildings of different heights.
    The Fruit Tree Scenario is designed for orchards that might have a large variation of elevations and heights.
    The 2D mapping algorithms are optimized for the three specific scenarios, so you can choose the one that best fits your mission type.

    3.A large black area appears on a map generated from 2D reconstruction.

    1. The head of the aircraft did not turn around during data acquisition, and the intrinsic parameter cx or cy of the aircraft is shown in Deezer 6.2.36.2 Crack APK + Activation Code (2021) aerotriangulation quality report as >5% than half the length and width of the images;
    2. The locations cover contrasting terrain, with roofs or hilltops captured in the shots, which resulted in a low overlap rate. You may re-shoot the images as needed.

    4.The edges of the building in a map generated from 2D reconstruction are distorted.

    1. The overlap rate is too low. You may re-shoot the images as needed;
    2. Make sure “Urban” is selected as the reconstruction scenario.

    5.Can I create a 2D reconstruction with oblique images?

    No.

    6.Why is there a large discrepancy between the elevation result in the digital surface model (DSM) of the 2D map generated by DJI Terra and the actual elevation measured via RTK?

    The location information on aerial images collected by a drone that’s not equipped with RTK is not the most accurate, which will result in a difference between the elevation in the digital surface model (DSM) and the actual elevation.
    When conducting missions with the Phantom 4 RTK, if the 2D map is generated with only the Nadir view images collected, the precision of the DSM will be limited, which is why it is recommended to incorporate oblique imagery in building the 2D map to enhance precision. This can be done by setting the gimbal pitch to -45° and circling the point of interest during flight.

    7.How different are the 3D models built at different resolutions? How long does it take to build models at these resolutions?

    There are three options for reconstruction resolution: high, medium, and low, which will generate models at full, half, and quarter resolution respectively. The higher the resolution the better the quality of the reconstructed models. The rough ratio of time consumption for reconstruction at high:medium: low resolutions is about 16:4:1.

    8.Can DJI Terra crop 2D and 3D models?

    Yes, this can be achieved before reconstruction. After aerial triangulation optimization is complete, crop 2D and 3D models by specifying the reconstruction area using the ROI modeling function.

    9.Why are there gaps in my model? What are some factors that affect the quality of the reconstruction?

    Gaps in the model can be due to missing shots of the area being mapped, 21 Flying Images 2.0 crack serial keygen, or images taken at poor angles. The quality of reconstruction can be affected by factors such as reflective surfaces in the area (water or glass), or large areas of the same color or pattern (white walls, skies).

    10.What should I keep in mind when creating reconstructions using images taken by an oblique camera array?

    You will need to define the camera parameters of each of the five cameras. The captured photos will be stored in five folders corresponding to each lens.
    In a folder, select all photos, right-click and go to Properties, click Details, scroll down to Camera Model, double-click the parameter value box on the right to go into edit mode, enter numbers or letters. Do this in all five folders for the five camears, the names should be different for each camera, for example it can be set to: 1, 2, 3, 4, 5 or A, B, C, D, E.

    11.The entire building in a map generated from 3D reconstruction is tilted to one side.

    The head of the aircraft did not turn around during data acquisition, and the intrinsic parameter cx or cy of the aircraft is shown in the aerotriangulation quality report as >5% than half the length and width of the images.

    12.The texture of the building’s facade in an image generated from 3D reconstruction is blurry.

    The tilted shots are missing. You may recapture the images as needed.

    13.Repetitive patterns of spots appear on a map result generated from 2D or 3D reconstruction.

    The spots may be caused by damage to your SD card or camera.

    14.Why did aerotriangulation fail, or why did I lose a large number of photos?

    1. Your RAM may be running low. Currently the processing speed is roughly 300-400 images/G, with no block partitions 21 Flying Images 2.0 crack serial keygen aerotriangulation. Divide the number of images imported by 300, and see if the result is greater than the current available RAM;
    2. The overlap rate of the images is too low. Has the overlap rate been adjusted to a lower level? Were there any big altitude changes? The overlap rate may need to be 2Flyer Screensaver Builder Pro 6.1 crack serial keygen for areas with greater altitude changes;
    3. The textures of objects are not captured in the images: Overexposure of water surfaces, white walls, the sky, 21 Flying Images 2.0 crack serial keygen, snowy grounds, 21 Flying Images 2.0 crack serial keygen, stadiums or other large structures under the sun;
    4. Repeated texture: Rice fields, solar panels, floor tiles, etc.;
    5. A large number of objects were in motion: Crowds, vehicle flows, sea waves, etc.;
    6. A large area captured in the image consists of objects not made of diffuse reflective materials: Mirrors, glass, reflective car surfaces, etc.;
    7. The angles of view differ greatly between the images (5-camera oblique system). The top-view image has been reconstructed, but most of the images for the tilted angles are lost;
    8. Image quality issues: Blurry movements, lack of focus, overexposure, etc.;
    9. Non-continuity in the images, missing shots, or importing multiple sets of data not applicable to the same area.

    15.What can I do to save a failed aerotriangulation or recover lost photos?

    1. Import the images into DJI Terra, and check their 2D locations on the map;
    - Multiple missions can be created to reconstruct the images separately if they are not continuous and can be clearly categorized into batches
    - You may capture additional images to fill in shots that may have been missed

    2. The 2D locations of the images are continuous and do not show noticeable gaps;
    - The reconstruction success rate is relatively low for images of large bodies of water such as the ocean; while for rivers and lakes, you should increase your mission altitude and make sure no more than 1/3 of any single photo is covered by water
    - You may recapture the images if the locations are in hilly terrain and the overlap rate is lower than 60%. You should fly the aircraft at a higher altitude and ensure a sufficient overlap rate

    3. Data was recorded from multiple trips, and the overlap rate between the trips is sufficient. Some trips do not appear in the reconstruction, while each trip can be reconstructed individually.
    - The lighting conditions should not differ too much between the environments where the data was acquired. If some trips were recorded in the morning, 21 Flying Images 2.0 crack serial keygen others were captured in the afternoon, the software may not be able to merge the data of different trips due to big contrasts in brightness

    16.The texture of a glass building is distorted, or holes appear on reflective objects like cars or on white walls or lake surfaces.

    1. Glass and car surfaces are not made of diffuse reflective materials. You may try shooting the images at a greater distance;
    2, 21 Flying Images 2.0 crack serial keygen. White walls and lake surfaces do not have textures. You may try shooting the images at a greater distance.

    17.What files 21 Flying Images 2.0 crack serial keygen I get from the 2D maps and 3D models built in DJI Terra?

    2D reconstructions:
    Results include map tiles shown in the app’s interface, digital orthophoto maps, and digital surface models in the GeoTIFF format used in UTM projections.

    3D reconstructions:
    Results contain a level of detail model in .osgb. b3dm, or .s3mb, texture mesh in .ply. obj, or .i3s, a point cloud in .pnts. las, or .s3mb, and an aerial triangulation result file in .xml or Terra's own format.

    18.What is the accuracy when building 2D maps and 3D models with the Phantom 4 RTK?

    When using the Phantom 4 RTK, the absolute accuracy achieved by the 2D maps in DJI Terra is around 1 to 2 times the GSD, which is a similar level of accuracy as other data processing software. When flying at 100m height, the absolute horizontal accuracy of the 2D map is 2-5cm, and the absolute accuracy of the 3D models is within 4cm, 21 Flying Images 2.0 crack serial keygen.

    19.What variables might affect the accuracy of the 2D and 3D reconstructions in DJI Terra?

    The accuracy of the reconstruction can be affected by factors such as camera distortion, image quality, flight height, side and forward overlap settings, GPS (RTK) positioning accuracy and the area’s texture information.

    20.How do I view the results and files from my aerotriangulation results, 2D maps and 3D point cloud or models?

    You can click the Open folder button in each Mission to open the file folders where the files generated from the missions are stored. Aerotriangulation results are stored under "AT", 2D maps are stored under “map” and 3D point cloud or models are stored under “models”.
    To view log files of reconstruction mission using Standalone computation, use Ctrl + Alt + L.

    21.Can I run multiple missions on the same computer?

    Due to limitations in the computer’s processing capacity, you can only run multiple reconstructions at the same time. They will be processed in the order in which they are added to the lineup.

    22.During reconstruction, a pop-up window that says "Cannot continue to execute 21 Flying Images 2.0 crack serial keygen because OpenCL.dll cannot be found. Reinstalling the program may solve this problem. " - What should I do?

    Please update the GPU driver.

    23.Why is my computer stuck when processing images locally to reconstruct a model? Can I run DJI Terra 21 Flying Images 2.0 crack serial keygen running other programs?

    To build reconstruction models as quickly as possible, DJI Terra uses all the computer resources available, including the CPU, RAM, and VRAM of the graphics card, which could make the computer slower while running DJI Terra but should not be a problem once the processing is finished.
    It is recommended that you don’t run other programs that might be GPU-intensive while running DJI Terra, as doing so could result in failure of model reconstruction.

    24.Does DJI Terra support reconstruction of regions of interest?

    Yes. After completing an aerotriangulation, you can set your region of interest and begin reconstruction.

    25.Are there any requirements for importing .prj files into DJI Terra?

    To allow a .prj file to be imported into DJI Terra, you must ensure the file follows a Esri-supported format and its projection or coordinate framework data are described in WKT character strings.

    26.Why did I get the error message: “JSON file read error”?

    1. Some of the value for horizontal or vertical accuracy in the POS data of your imported images is 0;
    2. The horizontal or vertical accuracy for the image GCP is set at 0 (we recommend updating to version 2.2.1 and above which has an automatic fault tolerance mechanism).

    27.Can I add an output format after 3D reconstruction is complete?

    Yes, after 3D reconstruction is complete, you can continue reconstruction by checking the required output format.

    Output Coordinate System
    1.What’s the purpose of setting an output coordinate system?

    The following reconstruction results can be delivered in specified coordinate systems.
    2D Reconstruction Results: dsm.tif、result.tif
    3D Reconstruction Results: LAS files, OBJ files, 21 Flying Images 2.0 crack serial keygen, PLY files, 21 Flying Images 2.0 crack serial keygen files, PCD files, S3MB files, I3S files. Each file comes with a coordinate system instruction file metadata.xml.

    2.Why do I get an “Output Coordinate System Error” pop-up after I set the output coordinate system and click Reconstruct?
    This error will pop up if reconstruction results cannot be converted to the specified coordinate system. The output coordinate system has to do with GPS information on the images and the coordinate system the GCPs are in, 21 Flying Images 2.0 crack serial keygen. Here are some scenarios that you might want to consider:
    (1) Aerial triangulation without GCPs


    (2) Aerial triangulation optimized with GCPs
    Ground Control Points (GCPs)
    1.What are Ground Control Points? How to obtain Ground Control Points?

    Ground Control Points (GCPs) are marked points on the ground with known coordinates and are clearly visible in an image. GCPs can be obtained using photogrammetry methods such as GPS-RTK or a total station.

    2.Why use GCPs?

    GCPs help increase the robustness and accuracy of aerial triangulation, check the accuracy of the aerial triangulation against actual measurements, and determine absolute orientation by converting the aerial triangulation result into GCPs in the designated coordinate system.

    3.What should be noted when importing GCP files?

    The GCP data should be in this order: point name, latitude/X, longitude/Y, height/Z, horizontal accuracy, vertical accuracy).Accuracy data is optional. The first row is coordinate data, and each column is separated with a space or a tab. In the projected coordinate system, X represents the East, and Y represents the North.

    4.What are the differences between GCPs and check points?

    GCPs are used to optimize the result of aerial triangulation. It would take at least three GCPs to ensure absolute orientation for aerial triangulation.
    Check points are used to check for the absolute accuracy of aerial triangulation by comparing the error between the result calculated with aerial triangulation and the actual measurements.
    It is recommended to use no less than four GCPs for calculation in each target area.
    When you have an 21 Flying Images 2.0 crack serial keygen number of GCPs, you can choose to set some of them as check points to check for accuracy.

    5.How accurate should the GCPs be?

    GCPs values are used 21 Flying Images 2.0 crack serial keygen aerial triangulation, and the accuracy should correspond to the final absolute accuracy that your project needs.
    The smaller the accuracy settings, the stronger the GCP’s contribution will be to the triangulation model.

    6.What is a GCP reprojection error?

    When computing a point and GCPs have been marked on at least 2 images, the 3D coordinates will be calculated and reprojected onto all images in which the point appears. The difference between the marked point and reprojected point on the image is the reprojection error. the average of different reprojection errors is shown in DJI Terra as the reprojection error.

    7.What is a GCP 3D error?

    The 3D error of a GCP refers to the spatial difference between its measured coordinates and 3D coordinates obtained by conducting space intersection with the elements of interior and exterior orientations of the image.

    8.What are some ways to optimize the results after marking a GCP?

    Given that the coordinate system in which aerial images and GCPs have been acquired can be converted using DJI Terra, i.e. the images and GCPs use the same coordinate system geodetic datum:
    a) For images with high positioning accuracy, for instance, ones acquired using the Phantom 4 RTK, GCP projections will not be far off from actual measurements. Mark the GCPs with reference to their projected results on the image, and then click “aerial triangulation” on the screen.
    b) For images with low positioning precision, you can run aerial triangulation first with the imported images that contain GPS information, and then import the measured coordinates of the GCPs. After the first triangulation, you can proceed with marking the GCPs and run an optimization by pressing “optimize” on the screen.

    9.What is the difference between aerial triangulation and optimization?

    An optimization is done to improve results of aerial triangulation. If a triangulation is done immediately after marking GCPs, check points will 21 Flying Images 2.0 crack serial keygen be used in the calculation, which is not ideal. A better process will be: aerial triangulation enter GCP coordinates and mark them against projected coordinates on the image optimize. By doing so, GCPs are used to improve the accuracy of aerial triangulation.

    10.I have imported all images and am now on the GCP Management page, but why do I not see the position and attitude information of the camera?

    Make sure the positioning and attitude information of the imported images is correct.

    11.Why are the GCPs and camera attitude/position not showing up in the right place after importing GCPs?

    Make sure the positioning and attitude information on the images are correct, and choose the same coordinate system as the one that the GCPs are set in.

    12.Why is the accuracy of check points lower after WinRAR Download 6.02 With Crack Full Version [ Latest 2021] using GCPs?

    The accuracy of aerial triangulation and optimization are affected by three factors: error in GCP marking, error in coordinate measurement, and the distribution and number of GCPs within the mapping area.
    We recommend you choose at least four GCPs distributed evenly across the target area. Each GCP should appear in at least four images at different locations, and avoid having it near the edge of an image.

    13.Does DJI Terra support GCP processing for images taken with other DJI drones?

    Yes.

    14.I've imported GCPs, but why aren't they showing up in aerial triangulation?

    1. The coordinate systems do not match. Make sure the coordinate system of the GCPs is the same as that of the selected GCPs, and the coordinate system of the imported POS data is the same as the selected POS data.
    2. The coordinate systems cannot be converted from one to the other. Make sure the coordinate system of the image POS data can be converted into the coordinate system of the GCPs. If not, please convert systems using a third-party software program.
    3. Height errors. Check the height differences between the coordinate systems of the imported 21 Flying Images 2.0 crack serial keygen data and GCPs. If there are errors, adjust them in the POS data settings.

    POS Data
    1.When do I need to import POS data?

    1. If you are looking to acquire results in a particular height or coordinate system (e.g. a local height or coordinate system that might not be included in Terra's existing database) without GCPs.
    2. If you are looking to process POS data and GCPs in the same height or coordinate system, you might need to import POS data and GCP data that have already been converted to said system.

    2.How do I set the coordinate system and height error of the POS data?

    The coordinate system setting of the POS data needs to correspond to the actual system written in the data, 21 Flying Images 2.0 crack serial keygen. Any height errors need to be adjusted for in the settings. You can preview the height values after adjusting all the POS import settings.

    3.What should I keep in mind when setting the POS data 21 Flying Images 2.0 crack serial keygen. Set to default DJI Terra accuracy. If the images contain RTK information and it is fixed, DJI Terra will read this data automatically and set the accuracy as follows: horizontal accuracy: 0.03 m, elevation accuracy: 0.06 m. If no RTK information is available or if it is not fixed, horizontal accuracy will be set to 2 m and vertical accuracy 10 m.
    2. Set accuracy values manually. Edit the horizontal and vertical accuracy values into Ahead Nero InCD Nero Digital Plugin 4.3.14.1 crack serial keygen POS data files and choose the corresponding column in in the POS import settings.

    4.What happens in aerial triangulation calculations if some of the images lack POS data?

    These images will not be UltraEdit 28.10.0.154 Crack + Serial Key Free Download [2021] in aerial triangulation calculations.

    5.Should I turn on POS Constraint for image processing during aerial triangulation?

    Generally, you should keep it on, but turn it off if the image POS data and the GCPs are not in the same height system.

    Cluster Reconstruction
    1.What computer equipment configuration is required for cluster reconstruction?

    Please refer to Preparation Before Using DJI Terra available on the download VoiceMod Pro 1.2.6.8 With Full Version Crack (TESTED) can I set up a local area network (LAN)?

    Please refer to Preparation Before Using DJI Terra available on the download page.

    3.What is the maximum number of photos that can be processed through cluster reconstruction?

    Depending on the highest computer RAM configuration, 1GB of free RAM can handle 8 gigapixels of data (approximately 400 Phantom 4 RTK images).

    4.What is a control device? What is a worker device?

    Each computer connected to a local network is either a control device or a worker device. A control device assigns reconstruction missions (and also undertakes part of the computing work), while reconstruction 21 Flying Images 2.0 crack serial keygen run mainly on worker device.

    5.Do control devices need to be bound with a license?

    Yes.

    6.Do worker devices need to be bound with a license? Can worker devices be replaced?

    Binding is not necessary. Worker devices can be replaced as needed.

    7.Can control devices be turned on at the same time in the same local area network (LAN)?

    Yes.

    8.Can the number of worker devices be increased after the cluster version license is activated?

    Yes. For details, please refer to Preparation Before Using DJI Terra.

    9.Which software should be used to open worker devices?

    DJI TERRA ENGINE

    10.What is the purpose of the Shared Directory?

    It is used to store original image data, temporary outputs and reconstruction outputs.

    11.Does aerotriangulation support cluster reconstruction?

    Yes.

    12.Can Aerotriangulation Cluster Computation increase the speed of aerotriangulation calculation? In what situations is Aerotriangulation Cluster Computation applicable?

    1. If Aerotriangulation Cluster Computation is enabled, DJI Terra will automatically estimate the computing speed of the standalone and the cluster and select the more efficient option. If this feature is disabled, DJI Terra will perform the reconstruction in standalone computing mode.
    2. It is recommended to enable Aerotriangulation Cluster Computation when the number of photos exceeds 8,000 and three or more worker devices participate in reconstruction.

    13.What is the role of the "Distance to Ground/Subjects" parameter?

    1. After aerotriangulation block splitting, the blocks need to partially overlap with a reasonable overlap rate. Therefore, the expansion distance of each block needs to be set. The setting of this parameter affects the expansion distance.
    2. The larger the block expansion distance, the slower the aerotriangulation calculation. The default value is suitable for most scenarios.

    14.What is the limit on photos processed when Aerotriangulation Cluster Computation is enabled?

    The limit on processed data is determined by the memory of the control device. In the control device, 1GB of available memory can be used to process about 6,000 images, so a 128GB control device can process about 800,000 images.

    15.What is the basis for aerotriangulation block splitting?

    DJI Terra 21 Flying Images 2.0 crack serial keygen aerotriangulation block splitting automatically based on the memory of the worker devices participating in the reconstruction. The worker device with the smallest amount of memory affects the size of the blocks (but does not affect the upper limit for processed data).

    16.How can I view the working status of worker devices?

    The reconstruction mission list displays the status of the worker devices currently participating in the reconstruction.

    17.How control device assign the work of worker devices during cluster reconstruction?

    Aerotriangulation: Automatically selects the worker device with the highest RAM to perform the aerotriangulation missions;
    Block reconstruction: When the number of blocks is larger than the number of worker devices, the worker devices will be used to the maximum extent.

    18.In cluster reconstruction, can a worker devices participate in the current reconstruction mission again after being restarted or released?

    No. To 21 Flying Images 2.0 crack serial keygen a restarted or released worker devices to participate in the current reconstruction mission, you can stop the mission and re-select the devices before continuing reconstruction.

    19.Why is the utilization rate of integrated graphics cards on worker devices higher than that of discrete graphics cards during reconstruction?

    Temporarily not to the step of using a discrete graphics card (integrated graphics cards are not used for computing on DJI Terra).

    20.The following prompt appears when opening the software: “Unable to continue code execution because MSVCR120.dll could not be found. Reinstalling the program may resolve this issue.”

    Download and install the application: https://download.microsoft.com/download/2/E/6/2E61CFA4-993B-4DD4-91DA-3737CD5CD6E3/vcredist_x64.exe

    21.No worker device can be found in the Local Network Worker Devices list.

    1. Ensure that the Shared Directory of the control devices and worker devices are consistent and the paths are accessible;
    2. Close the antivirus software and security software, then try searching again;
    3. Disable the firewall of the control and worker devices.
    4. Try searching again after 21 Flying Images 2.0 crack serial keygen the virtual network card (Network Settings → Change Adapter Option → Disable Networks Started with Hyper-V).

    22.There are already aerotriangulation results and the photos are stored on the local disk. Will it go through aerotriangulation again if using cluster to do point cloud or model reconstruction?

    No, the photos and existing aerotriangulation results will be automatically copied to the network-attached storage (NAS) for cluster Y!TunnelPro crack serial keygen prompt occurs for a worker device: “Script error.”

    1, 21 Flying Images 2.0 crack serial keygen. First, check if you are using software such as Microsoft OneDrive, Outlook, Microsoft Teams and Flash. The software can be uninstalled if not needed;

    2. If it is needed, you can try:
    (1) Updating the above software
    (2) Updating the Win10 system
    (3) Updating the driver
    (4) Performing the setting: IE security policy-allow dynamic scripts
    (5) Performing the setting: IE advanced settings-reset

    24.Will any problem with a single device affect the reconstruction mission?

    A single worker device error will not cause the reconstruction mission to fail. Any failed worker device mission will be redistributed by the control device. If the redistributed worker device also has errors, the reconstruction mission will fail.

    25.Do cluster missions support resuming from a breakpoint?

    Yes.

    26.Where can I get the logs of cluster reconstruction missions?

    1. In the control device, open DJI Terra, press Ctrl+Alt+L, find all logs for the corresponding time period of the failed mission in the folder and export the logs;
    2. Under the shared directory, find all logs of the log folder [workers_log] corresponding to the mission and export them;
    3. SDK_log.txt in the models (3D) 21 Flying Images 2.0 crack serial keygen map (2D) folder in the cache directory of that mission.

    27.Why are all worker devices in the preparing state at certain stages of reconstruction, while some worker devices are in the working state and the others in the preparing state at certain other stages?

    The reconstruction process is divided into several stages which should be carried out in sequence. Some stages are completed independently on the control device, at which point all worker devices will be in the preparing state.
    Some stages are split into multiple missions which are then assigned to the worker device for processing. The worker devices that have completed the missions assigned will be in the preparing state, and will enter the next reconstruction stage after the other worker devices have also completed their processing.

    Zenmuse L1 LiDAR Point Cloud Process
    1.Do I need to purchase a license to use the DJI Terra LiDAR to process point cloud?

    No, LiDAR point cloud is a free feature, but if you need to use the point cloud accuracy optimization feature, you need to purchase the license for the professional version or higher.

    2.Does LiDAR point cloud mission create 3D models?

    No.

    3.Which data should be imported when doing the LiDAR point cloud process?
    Imported folders must include LiDAR point cloud data, RTK data, IMU data, whereas JPEG data can be imported when needed (select the folder named after data collection time).

    4.What would be the format of the output of the route document?
    The format for the route document will be in .out, a SBET and a SMRMSG document, and the format definition is as follows:

    SBET Format

    SMRMSG Format
    5.What is the point cloud effective distance? How do I set up a point cloud effective distance? Under which scenes do I need to set up?

    1. Point cloud effective distance: The point cloud that exceeds the distance from the LiDAR will be filtered during post-processing.
    2. How to set up a point cloud effective distance: Estimate the maximum straight-line distance between the location of LiDAR and the corresponding target area when collecting data.
    3. Under which scenes to set up: When reconstructing a closer measuring area, and when distant background areas are inevitably collected, you can set up an effective distance to get a better result for point cloud.

    6.What Microsoft Office 2020 Crack + License key Free Download point cloud accuracy optimization? When do I need to turn on point cloud accuracy optimization?

    1. Point cloud accuracy optimization: Optimize point cloud data scanned at different times to make the overall point cloud accuracy higher.
    2. When to turn on 21 Flying Images 2.0 crack serial keygen cloud accuracy optimization: When it is off, if the results contain obvious layer malposition, turn on the point cloud accuracy optimization feature to fix the problem.

    7.What is the default output coordinate system? Can I modify the coordinate?

    The default coordinate system is WGS84 and can be modified.

    8.How do I process a point cloud file when it is too large?

    You are recommended to separate it into multiple tasks for processing.

    9.What does the value of the Colorbar reflectivity mean? And what would be the range?

    The reflectivity of the measured target is between 0 - 255, where 0 to 150 correspond to the reflectivity within the range of 0 to 100% in the Lambertian reflection model; 151 to 255 correspond to the reflectivity of target objects with retroflection properties.

    10.What information does LAS file record?

    The 3D coordinates, RGB color, reflectivity, GPS timestamp, number of returns, the actual return number, and scanning angle of the points are recorded, along with the total number of points corresponding to each return, the software and version corresponding to the generated results, and the geographic coordinate system.

    11.What output formats of the files does LiDAR point cloud process?

    .pnts. las. s3mb. ply, and .pcd

    About Zenmuse L1 calibration
    1.How often does the Zenmuse L1 device need to be calibrated?

    The calibration frequency varies according to actual usage. When the point cloud post-processing results 21 Flying Images 2.0 crack serial keygen layered, inaccurate color rendering, or the device is accidentally dropped, you can use the Zenmuse L1 Calibration mode for processing, and then export the calibration file to the remote control for device calibration, 21 Flying Images 2.0 crack serial keygen.

    2.How do I plan routes for collecting calibration materials?

    It is recommended to use DJI Pilot to plan the route for collecting calibration materials. The requirements for route planning are as follows:
    1. Surveying area: A surveying area at least 300m X 300m with obvious texture features and building facades.
    2. The oblique photography route is recommended, with the Repeat Scan Mode enabled, a route speed ≥10m/s, a route height of 100m, a forward overlap ratio of ≥80%, and a side overlap ratio of ≥60%.
    3. Model coloring must 21 Flying Images 2.0 crack serial keygen enabled (when collecting visible-light photos).
    4. You can use either RTK or PPK.

    3.After the data is imported and the calibration process is completed, how do I check whether the calibration is compliant with the standard?

    1. Checkpoints can be set up in the surveying area, so that you can verify the accuracy of checkpoint based on the calibration route reconstruction results. If the accuracy reaches the engineering project accuracy, the calibration is compliant.
    2. Observe whether the coloring of the point cloud results is accurate, and no layered.

    About Zenmuse P1 calibration
    1.How should I design the calibration route and set parameters? Is RTK required for route collection?

    The calibration 21 Flying Images 2.0 crack serial keygen can be designed using 5-heading tilt-shift photography or traditional 5-route oblique photography.

    To achieve a more reliable calibration result, the following parameters are recommended:
    - Capturing no less than 500 images
    - The front overlap is no less than 80%
    - The side overlap is no less than 70%
    - The proportion of oblique images is not less than 2/3
    - A calibration scenario with a large elevation difference area

    RTK is not required, but the quality of calibration results can be verified through RTK in connection with checkpoint layout.

    2.After reconstruction is complete, how do I check whether the route data meets the calibration standard?

    If RTK positioning data is available for calibration route collection, the accuracy of checkpoints can be verified based on the results of the calibration route reconstruction by deploying checkpoints in the survey area. If the accuracy meets the required engineering accuracy, the calibration meets the standard.

    If no RTK positioning data is available for calibration route collection, it is impossible to quantitatively evaluate whether the calibration result meets the standard. However, this can be verified based on the difference between the initial value and the optimized value of camera parameter focal length f and principal points cx, cy for oblique photography reconstruction after camera calibration. If there is no significant difference, the calibration can be considered as meeting the standard.

    3.How often should the load device be calibrated?

    How often the load device should be calibrated depends on actual use. It is recommended to calibrate the camera using the latest reconstruction calibration file when there is a significant difference between the initial value and the optimized value of camera parameter focal length f and principal points cx, cy in the reconstruction quality report, and the reconstruction result meets the engineering accuracy requirements.

    2D Multispectral Reconstruction
    1.What results can be exported from a 2D multispectral reconstruction?
    2.How are the vegetation indices calculated in the 2D multispectral reconstruction and what do they mean?
    3.Does the 2D Multispectral Construction mode also support data from other multispectral cameras other than the P4 Multispectral?

    Currently, no.

    4.Can I create 2D multispectral reconstructions without importing RGB images?

    No. Currently RGB images are required for 2D multispectral reconstructions.

    5.Can images of a particular band captured by P4 Multispectral be imported into DJI Terra for 2D multispectral reconstruction?

    Yes. You only need to import RGB images and images within the bands required by a particular vegetation index to perform a reconstruction.

    6.Is radiometric correction supported by 2D multispectral reconstruction?

    Yes, before reconstruction, calibration data can be imported for radiometric correction

    7.How many sets of calibration board data are supported for radiation calibration?

    Up to three sets of calibration board data are supported.

    Other
    1.Can I modify the location where my 2D and 3D reconstructions are saved?
    Yes. The default path is C:\Users\***(User Name)\Documents\DJI\DJI Terra. You can modify the path by going to setting icon>> setting icon>> Cache directory.
    2.Can I import models generated in DJI Terra into other software programs, such as Maya, Blender, SketchUp, and 3ds Max?

    Yes, the .obj files generated in DJI Terra can 21 Flying Images 2.0 crack serial keygen imported into Maya, Blender, SketchUp, and 3ds Max. Look up tutorials for the specific process for each software.

    3.Can I embed a 3D model into a webpage?

    Yes. b3dm. osgb. ply and .obj files generated by DJI Terra are universal file formats and can be embedded into webpages. You can find instructions for embedding each of these formats online.

    4.Can I use non-aerial images to build 2D or 3D models?

    Theoretically they can be used to reconstruct 3D models although the quality might suffer. They cannot be used to build 2D reconstructions.

    5.Can I process images taken from non-DJI drones in DJI Terra to build 2D and 3D reconstructions?

    Theoretically yes for 3D models, but the results might not be as good as if you were to use DJI drones. The quality of the reconstructions will benefit from GPS or RTK positioning data on the images. Real-time 2D reconstructions are not supported.

    6.What are some keyboard shortcuts that I can use in DJI Terra?
    7.A prompt appears on DJI Terra saying that the maximum binding limit has been reached.

    1. Check if there has been any hardware changes with the computers bound to the software. Any hard disk location changes or CPU replacements will invalidate the previous binding settings;
    2. Check if you fortnite account bound any hardware device on a cloud server, such as Alibaba Cloud and Tencent Cloud, which will invalidate the previous binding settings.

    8.DJI Terra keeps loading and fails to start normally.

    1. Check if any other software (or a virus, Trojan horse, adware, etc.) has been installed on your computer that is preventing DJI Terra from establishing an internet connection. This can be solved by resetting the networks of the Windows system.
    2. Check if any VPN software has been enabled. If so, disable the VPN or configure the VPN correctly.

    9.The system says No license, Contact your local dealer.

    You will see the following data in the log:
    [GetAvailableFunc] iDate: 1596520841 iCurDate: 1596520513 iEndDate:1596729600
    [GetAvailableFunc] Local license out of date.
    iDate is the server’s time, and iCurDate is the current time of the user’s computer. The license cannot be used when iDate > iCurDate.
    Usually the value of iCurDate should be greater than iDate. It is possible that your computer’s clock is slow, 21 Flying Images 2.0 crack serial keygen. You may try resetting the time. Both Win7 and Win10 support automatic online time calibration. We suggest you enable this feature.

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    Trusted platform module security defeated in 30 minutes, no soldering required

    Trusted platform module security defeated in 30 minutes, no soldering required
    with 104 posters participating, including story author

    Let’s say you’re a large company that has just shipped an employee a brand-new replacement laptop. And let’s say it comes preconfigured to use all the latest, best security practices, including full-disk encryption using a trusted platform module, password-protected BIOS settings, UEFI SecureBoot, and virtually all other recommendations from the National Security Agency and NIST for locking down federal computer systems. And let’s say an attacker manages to intercept the machine. Can the attacker use it to hack your network?

    Research published last week shows that the answer is a resounding "yes." Not only that, but a hacker who has done her homework needs a surprisingly short stretch of time alone with the machine to carry out the attack. With that, the hacker can gain the ability to write not only to the stolen laptop but to the fortified network it was configured to connect to.

    Researchers at the security consultancy Dolos Group, hired to test the security of one client’s network, received a new Lenovo computer preconfigured to use the standard security stack for the organization. They received no ?orel x4 crack serial keygen credentials, configuration details, or other information about the machine. An analysis of the BIOS settings, boot operation, and hardware quickly revealed that the security measures in place were going to preclude the usual hacks, including:

    Fort Knox and the not-so-armored 21 Flying Images 2.0 crack serial keygen little else to go on, the researchers focused on the trusted platform module, or TPM, a heavily fortified chip installed on the motherboard that communicates directly with other hardware installed on the machine. The researchers noticed that, as is the default for disk encryption using Microsoft’s BitLocker, the laptop booted directly to the Windows screen, with no prompt for entering a PIN or password. That meant the TPM was where the sole cryptographic secret for unlocking the drive was stored.

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    Microsoft recommends overriding the default and using a PIN or password only for threat models that anticipate an attacker with enough skill and time alone with an unattended target machine to open the case and solder motherboard devices, 21 Flying Images 2.0 crack serial keygen. After completing their analysis, the researchers said that the Microsoft advice is inadequate because it opens devices to attacks that can be performed by abusive spouses, malicious insiders, or other people who have fleeting private access.

    “A pre-equipped attacker can perform this entire attack chain in less than 30 minutes with no soldering, simple and relatively cheap hardware, and publicly available tools,” the Dolos Group researchers wrote in a post, “a process that places it squarely into Evil-Maid territory.”

    TPMs have multiple layers of defenses 21 Flying Images 2.0 crack serial keygen prevent attackers from extracting or tampering with the data they store. For instance, an analysis more than 10 years ago by reverse-engineer Christopher revealed that a TPM chip made by Infineon was designed to self-destruct if it was physically penetrated, 21 Flying Images 2.0 crack serial keygen. Optical sensors, for instance, detected ambient light from luminous sources. And a wire mesh that covered the microcontroller was aimed at disabling the chip should any of its electrical circuits be disturbed.

    With little hope of cracking the chip inside the Lenovo laptop, the Dolos researchers sought other ways they might be able to extract the key that decrypted the hard drive. They noticed that the TPM communicated with the CPU using serial peripheral interface, a communications protocol for embedded systems.

    Abbreviated as SPI, the firmware provides no encryption capabilities of its own, so any encryption must be handled by the devices the TPM is communicating with, 21 Flying Images 2.0 crack serial keygen. Microsoft’s BitLocker, meanwhile, doesn’t use any of the encrypted communications features of the latest TPM standard. If the researchers could tap into the connection between the TPM and the CPU, 21 Flying Images 2.0 crack serial keygen might be able to extract the key.

    They wrote:

    Getting around the TPM in this manner is akin to ignoring Fort Knox and focusing on the not-so-armored car coming out of it.

    In order to sniff the data moving over the SPI bus, we must attach leads or probes to the pins (labeled above as MOSI, MISO, CS, and CLK) on the TPM. Normally that is simple but there is a practical problem in 21 Flying Images 2.0 crack serial keygen case. This TPM is on a VQFN32 footprint, which is very tiny. The “pins” are actually only 0.25mm wide and spaced 0.5mm apart. And those “pins” aren’t actually pins, they are flat against the wall of the chip so it’s physically impossible to attach any sort of clip. You could solder “fly leads” to the solder pads but that’s a hassle and tends to be a very physically unstable connection. Alternatively a common tactic is to locate in-series resistors to solder to, but they were just as small, and even more fragile. This was not going to be easy.

    But before we got started we figured there might be another way. Many times SPI chips share the same “bus” with other SPI chips. It’s a Sony Vegas Pro 19 Serial Number + Crack Torrent 2021 (Latest) hardware designers use to make connections simpler, save on cost, and make troubleshooting/programming easier. We started looking throughout the board for any other chip that might be on the same bus as the TPM. Maybe their pins would be larger and easier to use. After some probing and consulting the schematics, it turned out that the TPM shared a SPI bus with a single other chip, the CMOS chip, which definitely had larger pins. In fact, the CMOS chip had just about the largest pin size you can find on standard motherboards, it was a SOP-8 (aka SOIC-8).

    Short for complementary metal–oxide–semiconductor, a CMOS chip on a PC stores the BIOS settings, including the system time and date and hardware settings. The researchers connected a Saleae logic analyzer to the CMOS. In short order, they were able to extract every byte moving through the chip. The researchers then used the bitlocker-spi-toolkit written by Henri Numi to isolate the key inside the mass of data.

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    With the hard drive decrypted, the researchers combed through the data in search of something—encrypted or plaintext passwords, maybe exposed sensitive files or similar things—that might bring them closer to their goal of accessing the client’s network. They soon hit upon something: Palo Alto Networks’ Global Protect VPN client that had come pre-installed and preconfigured.

    One feature of the VPN is that it can establish a VPN connection before a user logs in. The capability is designed to authenticate an endpoint and enable domain scripts to run as soon as the machine powers on. This is useful because it allows admins to manage large fleets of machines without knowing the password for each one.

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    October 2021 Updates

    iOS: Litchi for DJI Mavic / Phantom / Inspire / Spark

    Version 2.10.0 / 2.10.1(October 7, 2021)
    - added support for Mavic Air 2
    - added waypoint mode for Mavic Mini 1 and Mavic Air 2
    - Facebook login is no longer supported. If you were using ESET NOD32 3.0 Antivirus for Win XP/2000/Vista (32-bit) 3.0.563 keygen to log in, 21 Flying Images 2.0 crack serial keygen migrate your Litchi account at https://flylitchi.com/facebooklogin
    - fixed a bug in Follow mode where the gimbal would not stay on the subject when there are elevation changes
    - fixed bug where Litchi Vue would fail to connect
    - fixed flickering bug with inspire 2 gimbal
    - misc improvements and bug fixes

    Android: Litchi for DJI Mavic / Phantom / Inspire / Spark

    Version 4.19.0(October 7, 2021)
    - added support for Mavic Air 2
    - added waypoint mode for Mavic Mini 1 and Mavic Air 2
    - added support for a secondary video feed for drones with multiple cameras
    - Facebook login is no longer supported. If you were using Facebook to log in, please migrate your Litchi account at https://flylitchi.com/facebooklogin
    - fixed a bug in Follow mode where the gimbal would not stay on the subject when there are elevation changes
    - misc improvements and bug fixes

    November 2020 Updates

    iOS: Litchi for DJI Mavic / Phantom / Inspire / Spark

    Version 2.9.1(November 24, 2020)
    - bug fix
    Version 2.9.0(November 21 Flying Images 2.0 crack serial keygen, 2020)
    - added support for Mavic Mini 1, all flight modes are supported except waypoint which will come in a future update
    - added Follow mode
    - Panorama Database has been revamped, stitching is improved and you can now stitch up to 130 megapixels spherical panoramas on iPhone and up to 220 megapixels on iPad Pro
    - added new "Auto Stitch Panoramas" general camera setting. When enabled, after shooting a panorama, 21 Flying Images 2.0 crack serial keygen, Litchi will automatically stitch it in low resolution in the background
    - added Simulator mode that can be used to simulate a flight, enable/disable it with a long press on the top bar's flight mode (requires a connection to the drone)
    - added new "Switch Flight Mode" custom function to switch the Mavic Mini's flight mode
    - added new Dynamic Homepoint setting
    - added support for Auto Exposure Bracketing (AEB) photo capture mode for Mavic Mini
    - AutoPano now shoots 360x110 spherical panoramas compared to 360x90 before
    - Mavic 2 Zoom's optical zoom is now correctly reported in the UI
    - fixed bug where sharing a panorama on Facebook would fail
    - misc improvements and bug fixes

    Android: Litchi for DJI Mavic / Phantom / Inspire / Spark

    Version 4.18.0(November 20, 21 Flying Images 2.0 crack serial keygen, 2020)
    - added support for Mavic Mini 1, all flight 21 Flying Images 2.0 crack serial keygen are supported except waypoint which will come in a future update
    - improved Follow mode
    - added Simulator mode that can be used to simulate a flight, enable/disable it with a long press on the top bar's flight mode (requires a connection to the drone)
    - added new "Switch Flight Mode" custom function to switch the Mavic Mini's flight mode
    - added support for Auto Exposure Bracketing (AEB) photo capture mode for Mavic Mini
    - AutoPano now shoots 360x110 spherical panoramas compared to 360x90 before
    - misc improvements and bug fixes

    November 2019 Updates

    iOS: Litchi for DJI Mavic / Phantom / Inspire / Spark

    Version 2.8.0(November 26, 2019)
    - when starting a waypoint mission, you can now choose to start at a specific waypoint rather than from the beginning
    - added new "Exit Waypoint Mission on Signal Loss" aircraft setting. When enabled, waypoint missions will end when signal is lost. When that happens, the drone will then execute the failsafe procedure (which can be changed with the "Signal Lost Behavior for Manual Flying" setting)
    - added new "Map Auto Zoom" general setting which lets you disable the map auto zoom
    - misc improvements and bug fixes
    Version 2.7.1(November 12, 21 Flying Images 2.0 crack serial keygen, 2019)
    - fixed Facebook login

    Android: Litchi for DJI Mavic / Phantom / Inspire / Spark

    Version 4.17.0(November 29, 2019)
    - added "Over Exposure Warning" general camera setting
    - added "Peak Focus Threshold" general camera setting
    Version 4.16.0(November 26, 2019)
    - when starting a waypoint mission, you can now choose to start at a specific waypoint rather than from the beginning
    - added new "Exit Waypoint Mission on Signal Loss" aircraft setting. When enabled, waypoint missions will end when signal is lost. When that happens, the drone will then execute the failsafe procedure (which can be changed with the "Signal Lost Behavior for Manual Flying" setting)
    - misc improvements and bug fixes

    October 2019 Updates

    iOS: Litchi for DJI Mavic / Phantom / Inspire / Spark

    Version 2.7.0(October 18, 2019)
    - added new mission setting "Photo Capture Interval" that can be used to automatically start an interval capture for the entire mission or between specific waypoints
    - misc bug fixes

    Android: Litchi for DJI Mavic / Phantom / Inspire / Spark

    Version 4.15.0(October 18, 2019)
    - added new mission setting "Photo Capture Interval" that can be used to automatically start an interval capture for the entire mission or between specific waypoints
    - added support for android 10
    - misc bug fixes

    Web: Mission Hub

    Version 1.4.0(October 18, 2019)
    - added 21 Flying Images 2.0 crack serial keygen mission setting "Photo Capture Interval" that can be used to automatically start an interval capture for the entire mission or between specific waypoints

    August 2019 Updates

    iOS: Litchi for DJI Mavic / Phantom / Inspire / Spark

    Version 2.6.7(August 27, 2019)
    - added new Tracking Quality setting in Track mode, set to High for improved tracking accuracy (only for powerful devices)
    - it is now possible to add a POI while a mission is in progress using the custom function "POI at Aircraft"
    - misc improvements and bug fixes

    Android: Litchi for DJI Mavic / Phantom / Inspire / Spark

    Version 4.14.0(August 27, 2019)
    - it is now possible to add a POI while a mission is in progress using the custom function "POI at Aircraft"
    - misc improvements and bug fixes

    June 2019 Updates

    iOS: Litchi for DJI Mavic / Phantom / Inspire / Spark

    Version 2.6.6(June 10, 2019)
    - misc bug fixes and improvements

    May 2019 Updates

    Android: Litchi for DJI Mavic / Phantom / Inspire / Spark

    Version 4.13.0(May 24, 2019)
    - added support for the DJI Smart Controller (installation steps)

    April 2019 Updates

    Android: Litchi for DJI Mavic / Phantom / Inspire / Spark

    Version 4.12.0(April 3, 2019)
    - bug fixes

    February 2019 Updates

    iOS: Litchi for DJI Mavic / Phantom / Inspire / Spark

    Version 2.6.5(February 25, 2019)
    - added support for Apple Maps
    - misc improvements and bug fixes

    Android: Litchi for DJI Mavic / Phantom / Inspire / Spark

    Version 4.11.0(February 25, 2019)
    - bug fixes

    January 2019 Updates

    iOS: Litchi for DJI Mavic / Phantom / Inspire / Spark

    Version 2.6.4(January 14, 2019)
    - misc bug fixes and improvements

    Android: Litchi for DJI Mavic / Phantom / Inspire / Spark

    Version 4.10.0(January 11, 2019)
    - added support for Mavic Tag Archives: Windows 10 program Enterprise
    - fixed Inspire 2 gimbal bug where it would be forced to switch to Free mode

    November 2018 Updates

    iOS: Litchi for DJI Mavic / Phantom / Inspire / Spark

    Version 2.6.3(November 21, 2018)
    - added support for Mavic 2 Enterprise
    - updated no fly zone system to support GEO 2.0
    - fixed Inspire 2 gimbal bug where it would be forced to switch to Free mode

    October 2018 Updates

    Web: Mission Hub

    Version 1.3.0(October 31, 2018)
    - added support for importing Digital Elevation Model (DEM) files

    September 2018 Updates

    iOS: Litchi for DJI Mavic / Phantom / Inspire / Spark

    Version 2.6.2(September 28, 2018)
    - fixed VR mode display issue when using iPhone XS Max
    Version 2.6.1(September 24, 2018)
    - fixed waypoint curve display issue
    Version 2.6.0(September 20, 2018)
    - added support for Mavic 2 Zoom/Pro

    Android: Litchi for DJI Mavic / Phantom / Inspire / Spark

    Version 4.9.0(September 20, 2018)
    - added support for Mavic 2 Zoom/Pro
    - fixed crash on Android 9 Pie
    - fixed bug where map zoom/rotate gestures would not always work
    - fixed pano bug when 'grid pattern' was set to 'spherical'

    Web: Mission Hub

    Version 1.2.3(September 20, 2018)
    - KML 3D Path export improvements

    August 2018 Updates

    iOS: Litchi for DJI Mavic / Phantom / Inspire / Spark

    Version 2.5.1(August 14, 2018)
    - fixed a crash that could happen when starting the app
    Version 2.5.0(August 13, 2018)
    - added support for Phantom 4 Pro V2
    - enabled waypoint and orbit mode for Spark
    - added support for Manual Focus mode
    - added 'Calibrate Lens' camera Booster Pro 7.6.0 License Key crack serial keygen, can be used to set Infinity Focus
    - the custom key 'Focus to Infinity' is now available for all drones with variable focus
    - the gimbal pitch angle in degrees is now displayed in the UI
    - added camera exposure settings to the VR mode on-screen display
    - added 'Transmission Channel' setting for Mavic Air/Spark
    - added 'Frequency Band' setting for Phantom 4 Pro V2
    - added 'Lock Gimbal when Shooting Photos' setting
    - added 'Sync Gimbal Yaw with Aircraft Heading' setting
    - added 'Show VPS Height when Used' setting
    - fixed an issue where the VR mode would stretch too much on iPhone X
    - fixed a display bug with the pause button in waypoint mode

    Android: Litchi for DJI Mavic / Phantom / Inspire / Spark

    Version 4.8.0(August 13, 2018)
    - added support for Phantom 4 Pro V2
    - enabled waypoint and orbit mode for Spark
    - added support for Manual Focus mode
    - added 'Calibrate Lens' camera setting, can be used to set Infinity Focus
    - added 'Focus to Infinity' custom function, available for all drones with variable focus
    - waypoint missions now show distance info between waypoints
    - added shutter and aperture priority exposure modes for drones that support them
    - the gimbal pitch angle in degrees is now displayed in the UI
    - added camera exposure settings to the VR mode on-screen display
    - added 'Transmission Channel' setting for Mavic Air/Spark
    - added 'Frequency Band' setting for Phantom 4 Pro V2
    - added 'Lock Gimbal when Shooting Photos' setting
    - added 'Sync Gimbal Yaw with Aircraft Heading' setting
    - added 'Show VPS Height when Used' setting
    - added 'Display Secondary Video Feed' setting for Inspire 2 and Matrice series
    - added custom function 'Switch Video Feed' for Inspire 2 and Matrice series
    - fixed a display bug with the pause button in waypoint mode

    July 2018 Updates

    Web: Mission Hub

    Version 1.2.2(July 20, 2018)
    - elevation features are now disabled by default and need to be enabled in the Hub settings before use
    Version 1.2.1(July 5, 2018)
    - exporting to CSV will now correctly export headings when the mission heading mode is set to "Auto"
    - elevation features can now only be used when logged in to a Litchi 21 Flying Images 2.0 crack serial keygen
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    - fixed bug where manually editing lat/long would not update the heading of waypoints which focus on Turbotax standard crack serial keygen POI

    June 2018 Updates

    iOS: Litchi for DJI Mavic / Phantom / Inspire / Spark

    Version 2.4.0(June 13, 2018)
    - pano mode speed and reliability improvements
    - pano mode settings revamp
    - when the general setting "Show GPS coordinates" is enabled, you can now edit waypoint GPS coordinates in their settings

    Android: Litchi for DJI Mavic / Phantom / Inspire / Spark

    Version 4.7.0(June 13, 2018)
    - pano mode speed and reliability improvements
    - pano mode settings revamp
    - fixed bug where changing the app's language would fail on some devices

    May 2018 Updates

    iOS: Litchi for DJI Mavic / Phantom / Inspire / Spark

    Version 2.3.0(May 25, 2018)
    - fixed bug where in some cases a waypoint mission could fail to start without showing a reason
    - fixed bug where the orbit speed could not be set without being connected to a drone
    - fixed bug where having more than 60 waypoints would cause lag
    - added new "Save to Panorama Database" pano setting

    Android: Litchi for DJI Mavic / Phantom / Inspire / Spark

    Version 4.6.1(May 24, 2018)
    - fixed bug where some flight modes would fail to start with Spark
    - performance improvements
    - added new map engine option: Mapbox

    Web: Mission Hub

    Version 21 Flying Images 2.0 crack serial keygen 24, 2018)
    - missions created in Mission Hub are now private by default instead of public

    April 2018 Updates

    iOS: Litchi for DJI Mavic / Phantom / Inspire / Spark

    Version 2.2.0(April 24, 2018)
    - added support for Mavic Air
    - fixed exposure compensation bug in Shutter/Aperture Priority modes

    Android: Litchi for DJI Mavic / Phantom / Inspire / Spark

    Version 4.6.0(April 24, 2018)
    - added support for Mavic Air
    - speed improvements for panoramas shot with Pano mode

    March 2018 Updates

    iOS: Litchi for DJI Mavic / Phantom / Inspire / Spark

    Version 2.1.4(April 5, 2018)
    - hotfixed bug with gimbal angles in waypoint missions
    Version 2.1.3(April 1, 2018)
    - hotfixed bug where interpolate gimbal angles would not always be correctly loaded
    Version 2.1.2(March 29, 2018)
    - added lock/unlock feature for mission editing; when loading a mission it will be locked for editing by default
    - improved support for altitudes above ground level in waypoint mode
    - fixed bug where in some cases the POI setting of a waypoint would not save windows product key Archives - Windows Activator

    Android: Litchi for DJI Mavic / Phantom / Inspire / Spark

    Version 4.4.2(March 29, 2018)
    - added lock/unlock feature for mission editing; when loading a mission it will be locked for editing by default
    - improved support for altitudes above ground level in waypoint mode
    - fixed bug where in some cases the POI setting of a waypoint would not save correctly

    February 2018 Updates

    Web: Mission Hub

    Version 1.1.9(Feb 13, 2018)
    - added support for altitudes relative to ground
    - added support for batch editing (using control/command + left click for multiple waypoints selection)
    - added new help section for Mission Hub: https://flylitchi.com/help#missionhub
    - added support for Visual Mission Planning with Google Earth Pro
    - altitudes now have up to 1 decimal of precision
    - improved support for CSV import/export
    - fixed bug where in some cases the POI setting of a waypoint would not save correctly

    Android: Litchi for DJI Mavic / Phantom / Inspire / Spark

    Version 4.4.1(Feb 27, 21 Flying Images 2.0 crack serial keygen, 2018)
    - fixed crash at startup on devices with intel processors
    Version 4.4.0(Feb 08, 2018)
    - added RTH/Land button in FPV mode
    - added Smart Return to Home general setting
    - added support for bluetooth controllers
    - misc bug fixes and improvements

    January 2018 Updates

    iOS: Litchi for DJI Mavic / Phantom / Inspire / Spark

    Version 2.1.1(Jan 18, 2018)
    - re-enabled Infinity Focus (Mavic Pro only)
    Version 2.1.0(Jan 11, 2018)
    - added support for x7 camera
    - updated to DJI SDK 4.4 which fixes the crash on 32 bit devices

    December 2017 Updates

    iOS: Litchi for DJI Mavic / Phantom / Inspire / Spark

    Version 2.0.0(Dec 22, 2017)
    - speed improvements for panoramas shot with Pano mode
    - added Auto Pano and Panorama database features (can be used for in-app panorama stitching and sharing), learn more at https://flylitchi.com/help#pano-p3
    - known issue in 1.19.0 and 2.0.0: Litchi will crash at startup on older iOS devices (iPhone 5, iPhone 5c, iPad 2, iPad 3, iPad 4 and iPad mini 1) due to a recent update from DJI's software libraries, we are working on restoring support for these devices

    November 2017 Updates

    iOS: Litchi for DJI Mavic / Phantom / Inspire / Spark

    Version 1.19.0(Nov 06, 2017)
    - added support for iPhone X
    - added RTH/Land button in FPV mode
    - added Smart Return to Home general setting
    - added support for bluetooth controllers
    - added "Find My Aircraft" in general settings
    - added a custom function to "Toggle FPV/Main Camera" (Inspire 2)

    August 2017 Updates

    iOS: Litchi for DJI Mavic / Phantom / Inspire / Spark

    Version 1.18.0(Aug 04, 2017)
    - added support for Spark: all flight modes are supported except waypoint/orbit at this time (if you are using Spark with the remote controller, you must connect using Wi-Fi between the RC and the mobile device, connecting via USB OTG is not currently supported)
    - added Tripod function in FPV mode (for supported drones only: Spark/Mavic Pro/Phantom 4 Adv-Pro/Inspire 2)
    - added custom function to "Toggle Tripod Mode"
    - added "Gimbal Gesture Control" general setting that lets you enable/disable the scroll movements on the video preview to move the gimbal
    - added "Show GEO Warning Zones" general setting that lets you show/hide GEO warning zones on the map
    - added a stop button in all flight modes that can be used to stop the current flight (waypoint, orbit, pano, focus, track)
    - a warning will now be shown when "Multiple Flight Mode" is disabled in DJI Go

    Android: Litchi for DJI Mavic / Phantom / Inspire / Spark

    Version 4.1.2(Aug 16, 2017)
    - fixed issue where the gimbal would not always rotate smoothly in waypoint missions
    Version 4.1.1(Aug 07, 2017)
    - bug fixes
    Version 4.1.0(Aug 04, 2017)
    - added support for Spark: all flight modes are supported except waypoint/orbit at this time (if you are using Spark with the remote controller, you must connect using Wi-Fi between the RC and the mobile device, connecting via USB OTG is not currently supported)
    - added Tripod function in FPV mode (for supported drones only: Spark/Mavic Pro/Phantom 4 Adv-Pro/Inspire 2)
    - added custom function to "Toggle Tripod Mode"
    - added a stop button in all flight modes that can be used to stop the current flight
    - a warning will now be shown when "Multiple Flight Mode" is disabled in DJI Go

    July 2017 Updates

    iOS: Litchi for DJI Mavic / Phantom / Inspire / Spark

    Version 1.17.2(Jul 17, 2017)
    - added Precision landing and Landing protection settings for Phantom 4
    - added support for polygon shaped no fly zones (for china)
    - misc improvements and bug fixes
    Version 1.17.1(Jul 11, 2017)
    - misc improvements and bug fixes
    Version 1.17.0(Jul 03, 2017)
    - with the latest DJI firmware for Mavic Pro (v01.03.0800 or higher), Phantom 4 Pro (v01.04.0602 or higher), Phantom 4 Advanced (v01.00.0128 or higher), Inspire 2 (v01.01.0010 or higher), Phantom 3 Standard (v1.9.20 or higher), 21 Flying Images 2.0 crack serial keygen, Phantom 3 4K (v1.6.50 or higher), Phantom 3 Advanced/Pro (v1.11.20 or higher), Phantom 4 (v02.00.0106 or higher), users in China are required to activate Litchi by logging into their DJI account at least once every three months, this can now be done within Litchi. Outside of China, Litchi will Dr Explain v3.1.207 crack serial keygen activate the application without requiring the user to log in within Litchi or DJI Go
    - added support for Phantom 4 Advanced
    - added "Over Exposure Warning" general camera setting
    - added "Enhance Display for D-Log Filter" general camera setting
    - fixed issue where the RC shutter button would not always use the selected capture mode
    - misc improvements and bug fixes

    Android: Litchi for DJI Mavic / Phantom / Inspire / Spark

    Version 4.0.2(Jul 17, 2017)
    - added Precision landing and Landing protection settings for Phantom 4
    - added "Send Feedback" button in the general settings
    - misc improvements and bug fixes
    Version 4.0.1(Jul 11, 2017)
    - misc improvements and bug fixes
    Version 4.0.0(Jul 05, 2017)
    - with the latest DJI firmware for Mavic Pro (v01.03.0800 or higher), Phantom 4 Pro (v01.04.0602 or higher), Phantom 4 Advanced (v01.00.0128 or higher), Inspire 2 (v01.01.0010 or higher), Phantom 3 Standard (v1.9.20 or higher), Phantom 3 4K (v1.6.50 or higher), Phantom 3 Advanced/Pro (v1.11.20 or higher), Phantom 4 (v02.00.0106 or higher), users in China are required to activate Litchi by logging into their DJI account at least once every three months, this can now be done within Litchi. Outside of China, Litchi will automatically activate the application without requiring the user to log in within Litchi or DJI Go
    - added support for Phantom 4 Advanced
    - added AutoFocus Continuous mode (AFC) for Mavic Pro, Phantom 4 Pro and X4S
    - fixed issue where the RC shutter button would not always use the selected capture mode
    - fixed licensing issue
    - misc improvements and bug fixes

    May 2017 Updates

    iOS: Litchi for DJI Mavic / Phantom / Inspire / Spark

    Version 1.16.2(May 24, 2017)
    - added "Share" button in the Facebook live settings giving you the ability to share your live stream on a friend's timeline or in a Facebook group
    - misc improvements and bug fixes
    Version 1.16.1(May 19, 2017)
    - upgraded Airdata UAV's free subscription offer from Gold to Pro plan
    Version 1.16.0(May 16, 2017)
    - added Facebook live streaming feature (tap on the share icon at the top right corner of the video preview to start it)
    - added "Cache Videos" setting. When enabled, recording videos with the drone will also 21 Flying Images 2.0 crack serial keygen Litchi to save the video to the "Litchi Video Cache" album in the Photos app
    - added "Cache Photos" setting. When enabled, photos you take will be EASEUS Data Recovery Wizard 14.2.0 Crack With License Key [Latest] to the 'Litchi Photo Cache' album (in the Photos app). Photo Caching does not work when the image format is set to RAW or when using the Interval capture mode. Photo Caching does not work during Waypoint, Pano and Track sessions
    - added "Photo Preview" setting. Requires "Cache Photos" setting to be enabled. When enabled, after taking a photo a preview will be shown along with a share button providing an easy way to share the photo to Facebook
    - added AutoFocus Continuous mode (AFC) for Mavic Pro, Phantom 4 Pro and X4S
    - added uplink/downlink signal information to the VR mode display
    - faster panoramas with Mavic Pro
    - reliability improvements for Pano mode
    - references to HealthyDrones replaced with its new name, Airdata UAV
    - fixed issue with M600/M600 Pro RC switch Xara 3d 6 crack serial keygen being recognized correctly
    - misc improvements and bug fixes

    Android: Litchi for DJI Mavic / Phantom / Inspire / Spark

    Version 3.10.10(May 24, 2017)
    - added "Share" button in the Facebook live settings giving you the ability to share your live stream on a friend's timeline or in a Facebook group
    - fixed issue where streaming with Facebook live using the Public or Friends privacy setting would instead appear as "Only me"
    - fixed issue where for some devices the Facebook Page profiles would not display correctly after a tap on the user's profile picture in the Facebook Live settings
    Version 3.10.9(May 19, 2017)
    - upgraded Airdata UAV's free subscription offer from Gold to Pro plan
    Version 3.10.8(May 16, 2017)
    - added Facebook live streaming feature (tap on the share icon at the top right corner of the video preview to start it)
    - added uplink/downlink signal information to the VR mode display
    - added autoland button in FPV mode
    - faster panoramas with Mavic Pro
    - reliability improvements for Pano mode
    - references to HealthyDrones replaced with its new name, Airdata UAV
    - fixed issue with M600/M600 Pro RC switch not being recognized correctly
    - misc improvements and bug fixes

    April 2017 Updates

    iOS: Litchi for DJI Mavic / Phantom / Inspire / Spark

    Version 1.15.9(Apr 07, 2017)
    - due to a bug in the DJI firmware, Focus, Track and VR with Immersive/Joystick Head Tracking modes are no longer usable with the following drone models and firmware versions: Mavic Pro (v01.03.0550 and v01.03.0500), Inspire 2 (v01.0.0240) and Phantom 4 Pro (v01.03.0418). If you are using one of these 21 Flying Images 2.0 crack serial keygen versions and wish to continue using the affected flight modes, either downgrade to wondershare Dr.Fone for Android crack serial keygen previous firmware version using the DJI Assistant 2 PC/Mac app or wait for DJI to release a new firmware that will fix this bug

    Android: Litchi for DJI Mavic / Phantom / Inspire / Spark

    Version 3.10.7(Apr 06, 2017)
    - due to a bug in the DJI firmware, Follow, Focus, 21 Flying Images 2.0 crack serial keygen and VR with Immersive/Joystick Head Tracking modes are no longer usable with the following drone models and firmware versions: Mavic Pro (v01.03.0550 and v01.03.0500), Inspire 2 (v01.0.0240) and Phantom 4 Pro (v01.03.0418). If you are using one of these firmware versions and wish to continue using the affected flight modes, either downgrade to a previous firmware version using the DJI Assistant 2 PC/Mac app or wait for DJI to release a new firmware that will fix this bug

    March 2017 Updates

    iOS: Litchi for DJI Mavic / Phantom / Inspire / Spark

    Version 1.15.8(Mar 21, 2017)
    - fixed hardware decoding bug
    - fixed issue where the battery serial would not correctly update in the flight logs when changing the battery
    - due to a bug in the DJI firmware, Focus, Track and VR 21 Flying Images 2.0 crack serial keygen Immersive/Joystick Head Tracking modes are no longer usable with the following drone models and firmware versions: Mavic Pro (v01.03.0500), 21 Flying Images 2.0 crack serial keygen, Inspire 2 (v01.0.0240) and Phantom 4 Pro (v01.03.0418). If you are using one of these firmware versions and wish to continue using the affected flight modes, either downgrade to a previous firmware version using the DJI Assistant 2 PC/Mac app or wait for DJI to release a new firmware that will fix this bug
    Version 1.15.7(Mar, 2017)
    - added shutter and aperture priority exposure modes
    - long press anywhere on the video preview to set Focus to Infinity for Mavic Pro
    - added custom function "Focus to Infinity" for Mavic Pro
    - added Burst shot x10/x14 capture modes for P4 Pro / Inspire 2
    - added Inspire 2 SSD settings
    - added FPV Camera support for Inspire 2
    - bug fixes for Phantom 3 4K

    Android: Litchi for DJI Mavic / Phantom / Inspire / Spark

    Version 3.10.6(Mar 20, 2017)
    - due to a bug in the DJI firmware, Follow, Focus, Track and VR with Immersive/Joystick Head Tracking modes are no longer usable with the following drone models and firmware versions: Mavic Pro (v01.03.0500), Inspire 2 (v01.0.0240) and Phantom 4 Pro (v01.03.0418). If you are using one of these firmware versions and wish to continue using the affected flight modes, either downgrade to a previous firmware version using the DJI Assistant 2 PC/Mac app or wait for DJI to release a new firmware that will fix this bug

    February 2017 Updates

    iOS: Litchi for DJI Mavic / Phantom / Inspire / Spark

    Version 1.15.6(Feb 13, 2017)
    - fixed rare issue with mavic pro battery not updating correctly
    Version 1.15.5(Feb 04, 2017)
    - added new "relative to ground" mode to set waypoint altitudes in the batch waypoint editor
    - panorama bug fix for Mavic Pro

    Android: Litchi for Voxengo Elephant 4 crack serial keygen Mavic / Phantom / Inspire / Spark

    Version 3.10.5(Feb 25, 2017)
    - fixed an issue with Mavic Pro where tap to focus would fail
    - fixed a Mavic Pro issue where it is not possible to control the gimbal manually when the app has control in waypoint mode (focus poi/interpolate)
    Version 3.10.4(Feb 14, 2017)
    - when uploading a waypoint mission, a progress window will now be shown
    Version 3.10.3(Feb 03, 2017)
    - follow me fix with Mavic Pro & P4 Pro
    - panorama bug fix for Mavic Pro
    - misc improvements and bug fixes

    January 2017 Updates

    iOS: Litchi for DJI Mavic / Phantom / Inspire / Spark

    Version 1.15.4(Jan 27, 2017)
    - a visual effect will now be shown when the drone is taking a photo
    - misc improvements and bug fixes
    Version 1.15.3(Jan 24, 2017)
    - added support 21 Flying Images 2.0 crack serial keygen Inspire 2
    - misc improvements and bug fixes
    Version 1.15.2(Jan 17, 2017)
    - fixed rare crash at startup on some devices
    - some diagnostic errors/warnings can now be closed

    Android: Litchi for DJI Mavic / Phantom / Inspire / Spark

    Version 3.10.2(Jan 26, 2017)
    - added support for Inspire 2
    - a visual effect will now be shown when the drone is taking a photo
    - misc improvements and bug fixes

    December 2016 Updates

    iOS: Litchi for DJI Mavic / Phantom / Inspire / Spark

    Version 1.15.1(Dec 22, 2016)
    - added "Active Collision Avoidance", "Landing Protection", "Precision Landing", "Frequency Band", "Lightbridge 2 Channel Switch" settings
    - added "JPEG Quality", "Video Caption", "Front LEDs Auto Turn Off", "Auto AE Unlock", "AF Focus Assistant" and "Video Coding" settings
    - fixed custom buttons C1/C2 conflict
    Version 1.15.0(Dec 19, 2016)
    - added support for Phantom 4 Pro
    - misc bug fixes

    Android: Litchi for DJI Mavic / Phantom 21 Flying Images 2.0 crack serial keygen Inspire / Spark

    Version 3.10.1(Dec 28, 2016)
    - fixed crash in the settings with Phantom 4
    Version 3.10.0(Dec 22, 2016)
    - added support for Phantom 4 Pro
    - added new "relative to ground" mode to set waypoint altitudes in the batch waypoint editor
    - added "Active Collision Avoidance", "Landing Protection", "Precision Landing", "Frequency Band" settings

    November 2016 Updates

    iOS: Litchi for DJI Mavic / Phantom / Inspire / Spark

    Version 1.14.3(Nov 22, 2016)
    - pano mode 21 Flying Images 2.0 crack serial keygen fix
    Version 1.14.2(Nov 17, 2016)
    - the "Center 21 Flying Images 2.0 crack serial keygen custom function can now be used in VR mode
    - fixed issue where in some cases a video decoder encryption error would incorrectly be shown
    - fixed issue where the battery would sometimes fail to connect
    Version 1.14.0 - 1.14.1(Nov 08, 2016)
    - added support for Mavic Pro
    - added "Ocusync Preview Quality" and "Ocusync Transmission Channel" general settings (Mavic Pro only)
    - added support for Landing confirmation
    - added "Full HD Stream" and "Portrait Mode" camera settings (Mavic Pro only)
    - added "5D button" key bindings in general settings (Mavic Pro only)
    - added new custom functions for "Digital Zoom In/Out", "AE Lock/Unlock" and "Toggle Portrait Mode"
    - added "Peak Focus Threshold" general camera setting
    - fixed issues with optical zoom

    Android: Litchi for DJI Mavic / Phantom / Inspire / Spark

    Version 3.9.2(Nov 29, 2016)
    - fixed bug where optical zoom with Z3 camera would not work
    - fixed bug where the phone camera's orientation would sometimes be incorrect in VR mode
    Version 3.9.1(Nov 25, 2016)
    - misc bug fixes
    Version 3.9.0(Nov 24, 2016)
    - added support for Mavic Pro
    - Pano mode revamp and optimizations
    - added support for Landing confirmation
    - added "Full HD Stream" and "Portrait Mode" camera settings (Mavic Pro only)
    - added "5D button" bindings (Mavic Pro only)
    - added new custom functions for "Digital Zoom In/Out", "AE Lock/Unlock""Center Autofocus" and "Toggle Portrait Mode"
    - setting the metering/autofocus is now done with a tap on the video preview
    - added support for optical zoom (C2 + left wheel)

    October 2016 Updates

    iOS: Litchi for DJI Phantom/Inspire

    Version 1.13.1(Oct 31, 2016)
    - added "Capture Strategy" setting in Pano mode, switch between "Column by Column" and "Row by Row"
    - added "Mode" setting in Pano mode, switch between "Aircraft Rotation" and "Gimbal Rotation" (Inspire 1/M100/M600/A3 only)
    - added "Nadirs" setting in Pano mode, allows selecting the number of Nadirs Litchi will take
    - added "Width" setting in Pano mode, which lets you shoot non spherical panoramas
    - added "Top Row Angle" setting in Pano mode, allows you to set the top row's pitch angle from 0 to +30°
    - added GEO restricted flight zones to the map
    - added setting to enable/disable GEO system, when disabled the app will use the previous NoFlyZone system (not up to date)
    - added more warning messages that will display when a problem is detected
    Version 1.13.0(Oct 24, 2016)
    - Pano mode revamp and optimizations
    - setting the exposure metering is now done with a tap on the video preview
    - triggering autofocus is now done with a tap on the video preview, switch between autofocus and exposure metering functions using the button at the top left corner of the video preview (X5/Z3/Mavic only)
    - added setting to show GPS coordinates
    - added "Center AutoFocus" custom function to trigger AutoFocus at the center
    - optical zoom can now be triggered using C2+left RC wheel
    - optical zoom bug fix
    - many UI improvements and bug fixes
    Version 1.12.4(Oct 13, 2016)
    - fixed screen recording crash on iOS 9
    Version 1.12.3(Oct 12, 2016)
    - fixed issue where sometimes video recording would restart mid-flight with auto record enabled
    Version 1.12.2(Oct 08, 21 Flying Images 2.0 crack serial keygen, 2016)
    - added optical zoom support (pinch to zoom on video preview) for Z3 and X5 zoom lens
    - added autofocus support for Z3 camera
    Version 1.12.1(Oct 06, 2016)
    - added lightbridge 2 setting to switch between LB/EXT video sources
    - fixed korean translation issue
    Version 1.12.0(Oct 05, 2016)
    - added Litchi Vue support (stream the video feed to a nearby iOS device running the Litchi Vueapp)
    - added initial support for z3 camera
    - fixed issue with map zoom

    Android: Litchi for DJI Phantom/Inspire

    Version 3.8.0(Oct 18, 2016)
    - added batch edit tool in waypoint mode
    - waypoint altitudes are now shown above each waypoint
    - remaining sdcard space is now shown in the settings
    - added terrain map type
    - misc bug fixes

    September 2016 Updates

    iOS: Litchi for DJI Phantom/Inspire

    Version 1.11.0(Sep 19, 2016)
    - added batch edit tool in waypoint mode
    - waypoint missions now show distance info between waypoints
    - remaining sdcard space is now shown in the settings
    - added Use Amap Imagery general setting (for China maps)
    - added terrain map type
    - the app now uses new database servers for missions saved to the cloud, be sure to update the app to continue using Mission Hub's features

    Android: Litchi for DJI Phantom/Inspire

    Version 3.7.0(Sep 19, 2016)
    - the app now uses new database servers for missions saved to the cloud, be sure to update the app to continue using Mission Hub's features

    August 2016 Updates

    iOS: Litchi for DJI Phantom/Inspire

    Version 1.10.2(Aug 11, 2016)
    - long press to autofocus will now also change the focus mode if not already on auto (X5 & X5R)
    - fixed autofocus and spot metering in photo mode 4:3
    - fixed issue with histogram in photo mode 4:3
    - updated translations
    Version 1.10.1(Aug 03, 2016)
    - added ability to move the gimbal using touch/drag on the video preview
    - updated translations
    - a broken SDcard icon will now be shown when there is a problem with the sdcard
    - max number of missions increased from 100 to 1000
    - fixed no sound when taking photos with the Interval capture mode
    - in flight logs, the channel will now show correct values for Auto
    - missions with empty names are no longer allowed

    Android: Litchi for DJI Phantom/Inspire

    Version 3.6.8(Aug 12, 2016)
    - long press to autofocus will now also change the focus mode if not already on auto (X5 & X5R)
    Version 3.6.7(Aug 11, 2016)
    - added how to connect help at app startup
    Version 3.6.6(Aug 09, 2016)
    - added battery info/settings panel, tap on battery icon to show it
    - added video recording time
    - replaced Gimbal FPV mode setting by Gimbal Mode setting
    - max number of missions increased from 100 to 1000
    - updated translations
    - fixed autofocus and spot metering in photo mode 4:3
    - fixed issue with histogram in photo mode 4:3

    July 2016 Updates

    iOS: Litchi for DJI Phantom/Inspire

    Version 1.10.0(Jul 15, 2016)
    - added support for the following languages: German, Italian, French, Russian, Chinese Simplified, Chinese Traditional, Spanish, Japanese, Czech, Dutch, Danish, Greek, Hungarian, Korean, Indonesian, Portuguese (Brazil), Portuguese (Portugal), Polish, Vietnamese, Finnish, Swedish, Turkish, Romanian
    - added language general setting
    - added battery info/settings, tap on battery icon to show the settings
    - added remaining flight time indicator
    - added digital zoom for Phantom 4
    - added Double Output (HDMI) general setting
    - fixed bug where the username would show as (null) when logged in via Facebook

    Android: Litchi for DJI Phantom/Inspire

    Version 3.6.5(Jul 13, 2016)
    - updated translations
    Version 3.6.4(Jul 08, 2016)
    - updated translations

    June 2016 Updates

    iOS: Litchi for DJI Phantom/Inspire

    Version 1.9.2(Jun 30, 2016)
    - fixed issue where the top bar status would allow to cancel a Landing caused by reaching the critical battery level
    Version 1.9.1(Jun 29, 2016)
    - added ability to set different speeds at each waypoint (only effective when the aircraft is in range of the RC)
    - added vision positioning general setting
    - when the aircraft is in Go Home/Landing modes, you can now tap on the top status bar to cancel the RTH/Landing
    - added ability to set exposure spot using single tap on video preview, when using spot metering mode
    - when starting the app, the last flight mode that was used will be selected
    - added load/save to Orbit mode
    - added long press bindings for C1/C2
    - added custom functions 'Toggle VR Immersive' and 'Toggle VR Joystick'
    - added ability to unlock map to have it rotate with the device heading
    - misc bug fixes
    Version 1.9.0(Jun 17, 2016)
    - added VR mode
    - added FPV mode with auto takeoff/land, course lock and home lock functions
    - added custom function to toggle the iphone camera in VR mode
    - added "Show Home Orientation" general setting, when enabled shows a line between home point and aircraft on the map
    - added gimbal work mode general setting
    - added gimbal FOV indicator for inspire 1 series 21 Flying Images 2.0 crack serial keygen fixed focus mode with aircraft rotation off for Inspire 1 series
    Version 1.8.0(Jun 07, 2016)
    - added voice feedback settings
    - added compass calibration in settings
    - added maximum altitude general setting
    - misc improvements and bug fixes

    Android: Litchi for DJI Phantom/Inspire

    Version 3.6.3(Jul 01, 2016)
    - updated translations
    Version 3.6.2(Jun 29, 2016)
    - added ability to set different speeds at each waypoint (only effective when the aircraft is in range of the RC)
    - added vision positioning general setting
    - when the aircraft is in Go Home/Landing modes, you can now tap on the top status bar to cancel the RTH/Landing
    - added ability to set exposure spot using single tap on video preview, when using spot metering mode
    - for X5 cameras, focus is now done with a long press
    - fixed bug with insert waypoint feature changing the altitude for other waypoints
    - removed "Minimum/Maximum selectable altitude" settings which now default to -200m (min) and 500m (max)
    - fixed bug where a space at the end of the email would cause failed logins
    Version 3.6.1(Jun 22, 2016)
    - misc bug fixes
    Version 3.6.0(Jun 22, 2016)
    - added 'Aircraft Head Tracking' in VR mode to control the aircraft yaw with your head
    - added home indicator in VR mode
    - added recording indicator in VR mode
    - added 'Show Home Orientation' general setting
    - added 'Mobile Camera (VR)' custom function with which you can toggle your mobile device's camera in VR mode
    - added 'Toggle VR Immersive' and 'Toggle VR Joystick' custom functions
    - added 1080p 120 fps recording resolution for Phantom 4
    - fixed inspire 1 yaw head tracking vr bug
    Version 3.5.0(Jun 06, 2016)
    - added in-app exposure settings (tap on exposure info panel at the top of the video preview to show the settings)
    - added voice instructions for compass calibration
    - minor tracking improvements for P3S when the camera is in photo mode and for the Nvidia Shield tablet in both camera modes
    - misc improvements and bug fixes

    May 2016 Updates

    iOS: Litchi for DJI Phantom/Inspire

    Version 1.7.0(May 20, 2016)
    - added ability to start one month free trial for Airdata UAV's Xtreme Toolkit Pro 15.2.1 crack serial keygen 360 Gold subscription (exclusive to Litchi), refer to https://flylitchi.com/airdata for more info
    - improvements to automatic gimbal control in waypoint mode
    - added object avoidance info (distance in meters) and sounds for Phantom 4
    - added RC Signal Lost general aircraft setting (only affects manual flying)
    - added Gimbal Pitch Extension general aircraft setting
    - added front LEDs general setting (also added as miracle 2.82 crack Archives function for C1/C2)
    - added collision avoidance general setting for Phantom 4
    - in Focus and Track 21 Flying Images 2.0 crack serial keygen for Inspire type aircrafts, the gimbal yaw will no longer be controlled when aircraft rotation is set to auto

    Android: Litchi for DJI Phantom/Inspire

    Version 3.4.0(May 20, 2016)
    - added ability to start one month free trial for Airdata UAV's HD 360 Gold subscription (exclusive to Litchi), refer to https://flylitchi.com/airdata for more info
    - improvements to automatic gimbal control in waypoint mode
    - added object avoidance info (distance in meters) and sounds for Phantom 4
    - added RC Signal Lost general aircraft setting (only affects manual flying)
    - added Gimbal Pitch Extension general aircraft setting
    - added front LEDs general setting (also added as custom function for C1/C2)
    - added collision avoidance general setting for Phantom 4
    - in Focus and Track modes for Inspire type aircrafts, the gimbal yaw will no longer be controlled when aircraft rotation is set to auto

    April 2016 Updates

    iOS: Litchi for DJI Phantom/Inspire

    Version 1.6.0(Apr 26, 2016)
    - you can now activate Follow in Track mode. When using Track's Follow feature always be ready to use the RC switch to regain control
    - smoother joystick controls in Track and Focus mode
    - added histogram in camera settings
    - screen recorder should be more reliable
    - gimbal roll can now be adjusted using C2 + right wheel
    Version 1.5.0(Apr 05, 2016)
    - added support for Phantom 4
    - added new Track mode which uses computer vision to track a selected object
    - added new Focus mode which uses GPS to focus on a subject
    - added all camera settings and exposure details panel
    - added support for Auto-Focus on tap (X5 and X5R only)
    - the C1 RC button setting is now enabled again
    - fixed hardware decoding setting not always applying correctly
    - fixed issue with waypoint mode finish action "Back to 1"

    Android: Litchi for DJI Phantom/Inspire

    Version 3.3.1(Apr 27, 2016)
    - fixed rare crash at startup on galaxy s6 devices
    Version 3.3.0(Apr 26, 2016)
    - added new Track mode which uses computer vision to track a selected object. When using Track's Follow feature always be ready to use the RC switch to regain control
    - Focus mode is now included in the base app, the base price has been adjusted accordingly
    - smoother joystick controls in Track and Focus mode
    - added histogram in general camera settings
    - added Focus on long press for X5 and X5R cameras
    - added Hue camera setting
    - misc bug fixes
    Version 3.2.1(Apr 01, 21 Flying Images 2.0 crack serial keygen, 2016)
    - hotfixed pano mode with gimbal rotations for Inspire 1
    Version 3.2.0(Mar 31, 2016)
    - added support for Phantom 4 (autonomous flights require P mode, switch to S or A to regain control)
    - improvements to Focus mode so movements should be less affected by wind
    - added AEB capture mode settings
    - panoramas taken in Pano mode with a P3/P4 should be more stable and less affected by wind
    - fixed bug where exposure info wasn't correctly updated in manual mode

    March 2016 Updates

    iOS: Litchi for DJI Phantom/Inspire

    Version 1.4.0(Mar 09, 2016)
    - added panorama mode
    - added grid lines camera setting

    Android: Litchi for DJI Phantom/Inspire

    Version 3.1.0(Mar 21, 2016)
    - improvements to panorama mode to make it more reliable

    February 2016 Updates

    iOS: Litchi for DJI Phantom/Inspire

    Version 1.3.1(Feb 13, 2016)
    - fix iPad Pro crash
    Version 1.3.0(Feb 12, 2016)
    - added Orbit flight mode
    - misc improvements and bug fixes

    Android: Litchi for DJI Phantom/Inspire

    Version 3.0.4(Feb 29, 2016)
    - improved POI transitions in Focus POI waypoint missions
    - fixed downlink signal bars not showing for some users
    - misc bug fixes
    Version 3.0.3(Feb 16, 2016)
    - fixed crash on some devices
    Version 3.0.2(Feb 15, 2016)
    - fixed compass error not removing itself after successful calibration
    - fixed a bug where in some cases no errors would be shown if the app failed to register with the DJI servers
    - fixed a bug where the P3 standard signal quality would not be stable
    - fixed wrong no fly zone warnings
    Version 3.0.1(Feb 12, 2016)
    - added support for P3 Standard, P3 4K, Inspire 1 Pro/Raw
    - removed P2 vision and P2 vision + support
    - 21 Flying Images 2.0 crack serial keygen aircraft model auto detection
    - added new camera shooting modes (HDR and AEB)
    - added new mission finish action Reverse
    - added ability to change the cruising speed while a mission is in progress
    - removed aircraft type and video decoder settings
    - misc improvements and bug fixes

    Источник: [https://torrent-igruha.org/3551-portal.html]

    An Overview of Cryptography

    1. INTRODUCTION

    Does increased security provide comfort to paranoid people? Or does security provide some very basic protections that we are naive to believe that we don't need? During this time when the Internet provides essential communication between literally billions of people and is used as a tool for commerce, social interaction, and the exchange of an increasing amount of personal information, security has become a tremendously important issue for every user to deal with.

    There 21 Flying Images 2.0 crack serial keygen many aspects to security and many applications, ranging from secure commerce and payments to private communications and protecting health care information. One essential aspect for secure communications is that of cryptography. But it is important to note that while cryptography is necessary for secure communications, it is not by itself sufficient. The reader is advised, then, that the topics covered here only describe the first of many steps necessary for better security in any number of situations.

    This paper has two major purposes, 21 Flying Images 2.0 crack serial keygen. The first is to define some of the terms and concepts behind basic cryptographic methods, and to offer a way to compare the myriad cryptographic schemes in use today. The second is to provide some real examples of cryptography in use today. (See Section A.4 for some additional commentary on this.)

    DISCLAIMER: Several companies, products, and services are mentioned in this tutorial. Such mention is for example purposes only and, unless explicitly stated otherwise, should not be taken as a recommendation or endorsement by the author.

    2. BASIC CONCEPTS OF CRYPTOGRAPHY

    Cryptography — the science of secret writing — is an ancient art; the first documented use of cryptography in writing dates back to circa 1900 B.C. when an Egyptian scribe used non-standard hieroglyphs in an inscription. Some experts argue that cryptography appeared spontaneously sometime after writing was invented, with applications ranging from diplomatic missives to war-time battle plans. It is no surprise, then, that new forms of cryptography came soon after the widespread development of computer communications. In data and telecommunications, cryptography is necessary when communicating over any untrusted medium, which includes just about any network, particularly the Internet.

    There are five primary functions of cryptography:

    1. Privacy/confidentiality: Ensuring that no one can read the message except the intended receiver.
    2. Authentication: The process of proving one's identity.
    3. Integrity: Assuring the receiver that the received message has not been altered in any way from the original.
    4. Non-repudiation: A mechanism to prove that the sender really sent this message.
    5. Key exchange: The method by which crypto keys are shared between sender and receiver.

    In cryptography, we start with the unencrypted data, referred to as plaintext. Plaintext is encrypted into ciphertext, which will in turn (usually) be decrypted back into usable plaintext. The encryption and decryption is based upon the type of cryptography scheme being employed and some form of key. For those who like formulas, this process is sometimes written as:

    21 Flying Images 2.0 crack serial keygen = Ek(P)
    P = Dk(C)

          where P = plaintext, C = ciphertext, E = the encryption method, D = the decryption method, and k = the key.

    Given 21 Flying Images 2.0 crack serial keygen, there are other functions that might be supported by crypto and other terms that one might hear:

    • Forward Secrecy (aka Perfect Forward Secrecy): This feature protects past encrypted sessions from compromise even if the server holding the messages is compromised. This is accomplished by creating a different key for every session so that compromise of a single key does not threaten the entirely of the communications.
    • Perfect Security: A system that is unbreakable and where the ciphertext conveys no information about the plaintext or the key. To achieve perfect security, the key has to be at least as long as the plaintext, making analysis and even brute-force attacks impossible. One-time pads are an example of such a system.
    • Deniable Authentication (aka Message Repudiation): A method whereby participants in an exchange of messages can be assured in the authenticity of the messages but in such a way that senders can later plausibly deny their participation to a third-party.

    In many of the descriptions below, two communicating parties will be referred to as Alice and Bob; this is the common nomenclature in the crypto field and literature to make it easier to identify the communicating parties. If there is a third and fourth party to the communication, they will be referred to as Carol and Dave, respectively. A malicious party is referred to as Mallory, an eavesdropper as Eve, and a trusted third party as Trent.

    Finally, cryptography is most closely associated with the development and creation of the mathematical algorithms used to encrypt and decrypt messages, whereas cryptanalysis is the science of analyzing 21 Flying Images 2.0 crack serial keygen breaking encryption schemes. Cryptology is the umbrella term referring to the broad study of secret writing, 21 Flying Images 2.0 crack serial keygen, and encompasses both cryptography and cryptanalysis.

    3. TYPES OF CRYPTOGRAPHIC ALGORITHMS

    There are several ways of classifying cryptographic algorithms. For purposes of this paper, they will be categorized based on the number of keys that are employed for encryption and decryption, and further defined by their application and use. The three types of algorithms that will be discussed are (Figure 1):

    • Secret Key Cryptography (SKC): Uses a single key for both encryption and decryption; also called symmetric encryption. Primarily used for privacy and confidentiality.
    • Public Key Cryptography (PKC): Uses one key for encryption and another for decryption; also called asymmetric encryption. Primarily used for authentication, non-repudiation, and key exchange.
    • Hash Functions: Uses a mathematical transformation to irreversibly "encrypt" information, providing a digital fingerprint. Primarily used for message integrity.

    FIGURE 1: Three types of cryptography: secret key, public key, and hash function.

    3.1. Secret Key Cryptography

    Secret key 21 Flying Images 2.0 crack serial keygen methods employ a single key for both encryption and decryption. As shown in Figure 1A, the sender uses the key to encrypt the plaintext and sends the ciphertext to the receiver. The receiver applies the same key to decrypt the message and recover the plaintext, 21 Flying Images 2.0 crack serial keygen. Because a single key is used for both functions, secret key cryptography is also called symmetric encryption.

    With this form of cryptography, it is obvious that the key must be known to both the sender and the receiver; that, in fact, is the secret. The biggest difficulty with this approach, of course, is the distribution of the key (more on that later in the discussion of public key cryptography).

    Secret key cryptography schemes are generally categorized as being either stream ciphers or block ciphers.

    A) Self-synchronizing stream cipher. (From Schneier, 1996, Figure 9.8)

    B) Synchronous stream cipher. (From Schneier, 1996, Figure 9.6)

    FIGURE 2: Types of stream ciphers.

    Stream ciphers operate on a single bit (byte or computer word) at a time and implement some form of feedback mechanism so that the key is constantly changing. Stream ciphers come in several flavors but two are worth mentioning here (Figure 2). Self-synchronizing stream ciphers calculate each bit in the keystream as a function of the previous n bits in the keystream. It is termed "self-synchronizing" because the decryption process can stay synchronized with the encryption process merely by knowing how far into the n-bit keystream it is. One problem is error propagation; a garbled bit in transmission will result in n garbled bits at the receiving side. Synchronous stream ciphers generate the keystream in a TeamViewer 15.11.6 Crack Archives independent of the message stream but by using the same keystream generation function at sender and receiver. While stream ciphers do not propagate transmission errors, they are, by their nature, periodic so that the keystream will eventually repeat.

    FIGURE 3: Feistel cipher. (Source: Wikimedia Commons)

    A block cipher is so-called because the scheme encrypts one fixed-size block of data at a time. In a block cipher, a given plaintext block will always encrypt to the same ciphertext when using the same key (i.e., it is deterministic) whereas the same plaintext will encrypt to different ciphertext in a stream cipher. The most common construct for block encryption algorithms is the Feistel cipher, named for cryptographer Horst Feistel (IBM). As shown in Figure 3, a Feistel cipher combines elements of substitution, permutation (transposition), and key expansion; these features create a large amount of "confusion and diffusion" (per Claude Shannon) in the cipher. One advantage of the Feistel design is that the encryption and decryption stages are similar, sometimes identical, requiring only a reversal of the key operation, thus dramatically reducing the size of the code or circuitry necessary to implement the cipher in software or hardware, respectively. One of Feistel's early papers describing this operation is "Cryptography and Computer Privacy" (Scientific American, May 1973, 228(5), 21 Flying Images 2.0 crack serial keygen, 15-23).

    Block ciphers can operate in one of several modes; the following are the most important:

    • Electronic Codebook (ECB) mode is the simplest, most obvious application: the secret key is used to encrypt the plaintext block to form a ciphertext block. Two identical plaintext blocks, then, will always generate the same ciphertext block. ECB is susceptible to a variety of brute-force attacks (because of the fact that the same plaintext block will always encrypt to the same ciphertext), as well as deletion and insertion attacks. In addition, a single bit error in the transmission of the ciphertext results in an error in the entire block of decrypted plaintext.
    • Cipher Block Chaining (CBC) mode adds a feedback mechanism to the encryption scheme; the plaintext is exclusively-ORed (XORed) with the previous ciphertext block prior to encryption so that two identical plaintext blocks will encrypt differently. While CBC protects against many brute-force, deletion, and insertion attacks, a single bit error in the ciphertext yields an entire block error in the decrypted plaintext block and a bit error in the next decrypted plaintext block.
    • Cipher Feedback (CFB) mode is a block cipher implementation as a self-synchronizing stream cipher. CFB mode allows data to be LEICA Geo Office Combined 7.0 crack serial keygen in 21 Flying Images 2.0 crack serial keygen smaller than the block size, which might be useful in some applications such as encrypting interactive terminal input. If we were using one-byte CFB mode, for example, each incoming character is placed into a shift register the same size as the block, encrypted, 21 Flying Images 2.0 crack serial keygen, and the block transmitted. At the receiving side, the ciphertext is decrypted and the extra bits in the block (i.e., everything above and beyond the one byte) are discarded. CFB mode generates a keystream based upon the previous ciphertext (the initial key comes from an Initialization Vector [IV]). In this mode, a single bit error in the ciphertext affects both this block and the following one.
    • Output Feedback (OFB) mode is a 21 Flying Images 2.0 crack serial keygen cipher implementation conceptually similar to a synchronous stream cipher. OFB prevents the same plaintext block from generating the same ciphertext block by using an internal feedback mechanism that generates the keystream independently of both the plaintext and ciphertext bitstreams. In OFB, a single bit error in ciphertext yields a single bit error in the decrypted plaintext.
    • Counter (CTR) mode is a relatively modern addition to block ciphers. Like CFB and OFB, CTR mode operates on the blocks as in a stream cipher; like ECB, CTR mode operates on the blocks independently. Unlike ECB, however, CTR uses different key inputs to different blocks so that two identical blocks of plaintext will not result in the same ciphertext. Finally, each block of ciphertext has specific location within the encrypted message. CTR mode, then, allows blocks to be processed in parallel — thus offering performance advantages when parallel processing and multiple processors are available — but is not susceptible to ECB's brute-force, deletion, and insertion attacks.

    A good overview of these different modes can be found at CRYPTO-IT.

    Secret key cryptography algorithms in use today — or, at least, important today even if not in use — include:

    • Data Encryption Standard (DES): One of the most well-known and well-studied SKC schemes, DES was designed by IBM in the 1970s and adopted by the National Bureau of Standards (NBS) [now the National Institute of Standards and Technology (NIST)] in 1977 for commercial and unclassified government applications. DES is a Feistel block-cipher employing a 56-bit key that operates on 64-bit blocks. DES has a complex set of rules and transformations that were designed specifically to yield fast hardware implementations and slow software implementations, although this latter point is not significant today since the speed of computer processors is several orders of magnitude faster today than even twenty years ago. DES was based somewhat on an earlier cipher from Feistel called Lucifer which, some sources report, had a 112-bit key. This was rejected, partially in order to fit the algorithm onto a single chip and partially because of the National Security Agency (NSA). The NSA also proposed a number of tweaks to DES that many thought were introduced in order to weaken the cipher; analysis in the 1990s, however, showed that the NSA suggestions actually strengthened DES, including the removal of a mathematical back door by a change to the design of the S-box (see "The Legacy of DES" by Bruce Schneier [2004]). In April 2021, the NSA declassified a fascinating historical paper titled "NSA Comes Out of the Closet: The Debate over Public Cryptography in the Inman Era" that appeared in Cryptologic Quarterly, Spring 1996.

      DES was defined in American National Standard X3.92 and three Federal Information Processing Standards (FIPS), all withdrawn in 2005:

      • FIPS PUB 46-3: DES (Archived file)
      • FIPS PUB 74: Guidelines for Implementing and Using the NBS Data Encryption Standard
      • FIPS PUB 81: DES Modes of Operation

      Information about vulnerabilities of DES can be obtained from the Electronic Frontier Foundation.

      Two important variants that strengthen DES are:

      • Triple-DES (3DES): A variant of DES that employs up to three 56-bit keys and makes three encryption/decryption passes over the block; 3DES is also described in FIPS PUB 46-3 and was an interim replacement to DES in the late-1990s and early-2000s.

      • DESX: A variant devised by Ron Rivest. By combining 64 additional key bits to the plaintext prior to encryption, effectively increases the keylength to 120 bits.

      More detail about DES, 3DES, and DESX can be found below in Section 5.4.

    • Advanced Encryption Standard (AES): In 1997, NIST initiated a very public, 4-1/2 year process to develop a new secure cryptosystem for U.S. government applications (as opposed to the very closed process in the adoption of DES 25 years earlier). The result, the Advanced Encryption Standard, became the official successor to DES in December 2001. AES uses an SKC scheme called Rijndael, a block cipher designed by Belgian cryptographers Joan Daemen and Vincent Rijmen. The algorithm can use a variable block length and key length; the latest specification allowed any combination of keys lengths of 128, 192, or 256 bits and blocks of length 128, 192, or 256 bits. NIST initially selected Rijndael in October 2000 and formal adoption as the AES standard came in December 2001. FIPS PUB 197 describes a 128-bit block cipher employing a 128- 192- or 256-bit key. AES is also part of the NESSIE approved suite of protocols. (See also the entries for CRYPTEC and NESSIE Projects in Table 3.)

      The AES process and Rijndael algorithm are described in more detail below in Section 5.9.

    • CAST-128/256: CAST-128 (aka CAST5), described in Request for Comments (RFC) 2144, is a DES-like substitution-permutation crypto algorithm, employing a 128-bit key operating on a 64-bit block. CAST-256 (aka CAST6), described in RFC 2612, is an extension of CAST-128, using a 128-bit block size and a variable length (128, 160, 192, 224, or 256 bit) key. GetFLV Pro 30.2108.1868 Crack + Registration Code Free {Latest-2021} is named for its developers, Carlisle Adams and Stafford Tavares, and is available internationally. CAST-256 was one of the Round 1 algorithms in the AES process.

    • International Data Encryption Algorithm (IDEA): Secret-key cryptosystem written by Xuejia Lai and James Massey, in 1992 and patented by Ascom; a 64-bit SKC block cipher using a 128-bit key.

    • Rivest Ciphers (aka Ron's Code): Named for Ron Rivest, a series of SKC algorithms.

      • RC1: Designed on 21 Flying Images 2.0 crack serial keygen but never implemented.

      • RC2: A 64-bit block cipher using variable-sized keys designed to replace DES. It's code has not been made public although many companies have licensed RC2 for use in their products. Described in RFC 2268.

      • RC3: Found to be breakable during development.

      • RC4: A stream cipher using variable-sized keys; it is widely used in commercial cryptography products. An update to RC4, called Spritz (see Cherry keygen,serial,crack,generator,unlock,key this article), was designed by Rivest and Jacob Schuldt. More detail about RC4 (and a little about Spritz) can be found below in Section 5.13.

      • RC5: A block-cipher supporting a variety of block sizes (32, 64, or 128 bits), key sizes, and number of encryption passes over the data. Described in RFC 2040.

      • RC6: A 128-bit block cipher based upon, and an improvement over, RC5; RC6 was one of the AES Round 2 algorithms.

    • Blowfish: A symmetric 64-bit block cipher invented by Bruce Schneier; optimized for 32-bit processors with large data caches, it is significantly faster than DES on a Pentium/PowerPC-class machine. Key lengths can vary from 32 to 448 21 Flying Images 2.0 crack serial keygen in length. Blowfish, available freely and intended as a substitute for DES or IDEA, is in use in a large number of products.

    • Twofish: A 128-bit block Cubase Pro 10.5.5 registration code Archives using 128- 192- or 256-bit keys. Designed to be highly secure and highly flexible, well-suited for large microprocessors, 8-bit smart card microprocessors, and dedicated hardware. Designed by a team led by Bruce Schneier and was one of the Round 2 algorithms in the AES process.

    • Threefish: A large block cipher, supporting 256- 512- and 1024-bit blocks and a key size that matches the block size; by design, the block/key size can grow in increments of 128 bits. Threefish only uses XOR operations, addition, and Spectrasonics Omnisphere 2.7 With Crack Free Download [2022] of 64-bit words; the design philosophy is that an algorithm employing many computationally simple rounds is more secure than one employing highly complex — albeit fewer — rounds. The specification for Threefish is part of the Skein Hash Function Family documentation.

    • Anubis: Anubis is a block cipher, co-designed by Vincent Rijmen who was one of the designers of Rijndael. Anubis is a block cipher, performing substitution-permutation operations on 128-bit blocks and employing keys of length 128 to 3200 bits (in 32-bit increments). Anubis works very much like Rijndael. Although submitted to the NESSIE project, it did not make the final cut for inclusion.

    • ARIA: A 128-bit block cipher employing 128- 192- and 256-bit keys to encrypt 128-bit blocks in 12, 14, and 16 rounds, depending on the key size. Developed by large group of researchers from academic institutions, research institutes, and federal agencies in South Korea in 2003, and 21 Flying Images 2.0 crack serial keygen named a national standard. Described in RFC 5794.

    • Camellia: A secret-key, block-cipher crypto algorithm developed jointly by Nippon Telegraph and Telephone (NTT) Corp. and Mitsubishi Electric Corporation (MEC) in 2000. Camellia has some characteristics in common with AES: a 128-bit block size, support for 128- 192- and 256-bit key lengths, and suitability for both software and hardware implementations on common 32-bit processors as well as 8-bit processors (e.g., smart cards, cryptographic hardware, and embedded systems). Also described in RFC 3713. Camellia's application in IPsec is described in RFC 4312 and application in OpenPGP in RFC 5581. Camellia is part of the NESSIE suite of protocols.

    • CLEFIA: Described in RFC 6114, CLEFIA is a 128-bit block cipher employing key lengths of 128, 192, and 256 bits (which is compatible with AES). The CLEFIA algorithm was first published in 2007 by Sony Corporation, 21 Flying Images 2.0 crack serial keygen. CLEFIA is one of the new-generation lightweight blockcipher algorithms designed after AES, 21 Flying Images 2.0 crack serial keygen, offering high performance in software and hardware as well as a lightweight implementation in hardware.

    • FFX-A2 and FFX-A10: FFX (Format-preserving, Feistel-based encryption) is a type of Format Preserving Encryption (FPE) scheme that is designed so that the ciphertext has the same format as the plaintext. FPE schemes are used for such purposes as encrypting social security numbers, credit card numbers, limited size protocol traffic, etc.; this means that an encrypted social security number, for example, would still be a nine-digit string. FFX can theoretically encrypt strings of arbitrary length, although it is intended for message sizes smaller than that of AES-128 (2128 points). The FFX version 1.1 specification describes FFX-A2 and FFX-A10, which are intended for 8-128 bit binary strings or 4-36 digit decimal strings.

    • GSM (Global System for Mobile Communications, originally Groupe Spécial Mobile) encryption: GSM mobile phone systems use several stream ciphers for over-the-air communication privacy. A5/1 was developed in 1987 for use in Europe and the U.S. A5/2, developed in 1989, is a weaker algorithm and intended for use outside of Europe and the U.S. Significant flaws were found in both ciphers after the "secret" specifications were leaked in 1994, however, and A5/2 has been withdrawn from use. The newest version, A5/3, employs the KASUMI block cipher. NOTE: Unfortunately, although A5/1 has been repeatedly "broken" (e.g., see "Secret code protecting cellphone calls set loose" [2009] and "Cellphone snooping now easier and cheaper than ever" [2011]), this encryption scheme remains in widespread use, even in 3G and 4G mobile phone networks. Use of this scheme is reportedly one of the reasons that the National Security Agency (NSA) can easily decode voice and data calls over mobile phone networks.

    • GPRS (General Packet Radio Service) encryption: GSM mobile phone systems use GPRS for data applications, and GPRS uses a number of encryption methods, offering different levels of data protection. GEA/0 offers no encryption at all. GEA/1 and GEA/2 are proprietary stream ciphers, employing a 64-bit key and a 96-bit or 128-bit state, respectively. GEA/1 and GEA/2 are most widely used by network service providers today although both have been reportedly broken. GEA/3 is a 128-bit block cipher employing a 64-bit key that is used by some carriers; GEA/4 is a 128-bit clock cipher with a 128-bit key, 21 Flying Images 2.0 crack serial keygen, but is not yet deployed.

    • KASUMI: A block cipher using a 128-bit key that is part of the Third-Generation Partnership Project (3gpp), formerly known as the Universal Mobile Telecommunications System (UMTS). KASUMI is the intended confidentiality and integrity algorithm for both message content and signaling data for emerging mobile communications systems.

    • KCipher-2: Described in RFC 7008, KCipher-2 is a stream cipher with a 128-bit key and a 128-bit initialization vector. Using simple arithmetic operations, the algorithms offers fast encryption and decryption by use of efficient implementations. KCipher-2 has been used for industrial applications, especially for mobile health monitoring and diagnostic services in Japan.

    • KHAZAD:KHAZAD is a so-called legacy block cipher, operating on 64-bit blocks à la older block ciphers such as DES and IDEA. KHAZAD uses eight rounds of substitution and permutation, with a 128-bit 21 Flying Images 2.0 crack serial keygen Designed in 2011, KLEIN is a lightweight, 64-bit block cipher supporting 64- 80- and 96-bit keys. KLEIN is designed for highly resource constrained devices such as wireless sensors and RFID tags.

    • Light Encryption Device (LED): Designed in 2011, LED is a lightweight, 64-bit block cipher supporting 64- and 128-bit keys. LED is designed for RFID tags, sensor networks, 21 Flying Images 2.0 crack serial keygen, and other applications 21 Flying Images 2.0 crack serial keygen devices constrained by memory or compute power.

    • MARS:MARS is a block cipher developed by IBM and was one of the five finalists in the AES development process. MARS employs 128-bit blocks and a variable key length from 128 to 448 bits. The MARS document stresses the ability of the algorithm's design for high speed, high security, 21 Flying Images 2.0 crack serial keygen, and the ability to efficiently and effectively implement the scheme on a wide range of computing devices.

    • MISTY1: Developed at Mitsubishi Electric Corp., a block cipher using a 128-bit key and 64-bit blocks, and a variable number of rounds. Designed for hardware and software implementations, and is resistant to differential and linear cryptanalysis. Described in RFC 2994, 21 Flying Images 2.0 crack serial keygen, MISTY1 is part of the NESSIE suite.

    • Salsa and ChaCha: Salsa20 is a stream cipher proposed for the eSTREAM project by Daniel Bernstein. Salsa20 uses a pseudorandom function based on 32-bit (whole word) addition, bitwise addition (XOR), and rotation operations, aka add-rotate-xor (ARX) operations. Salsa20 uses a 256-bit key although a 128-bit key variant also exists. In 2008, Bernstein published ChaCha, a new family of ciphers related to Salsa20. ChaCha20, originally defined in RFC 7539 (now obsoleted), is employed (with the Poly1305 authenticator) in Internet Engineering Task Force (IETF) protocols, most notably for IPsec and Internet Key Exchange (IKE), per RFC 7634, and Transaction Layer Security (TLS), per RFC 7905. In 2014, Google adopted ChaCha20/Poly1305 for use in OpenSSL, and they are also a part of 21 Flying Images 2.0 crack serial keygen. RFC 8439 replaces RFC 7539, and provides an ZoneAlarm Security Suite 7.0.302.000 crack serial keygen guide for both the ChaCha20 cipher and Poly1305 message authentication code, as well as the combined CHACHA20-POLY1305 Authenticated-Encryption with Associated-Data (AEAD) algorithm.

    • Secure and Fast Encryption Routine (SAFER): A series of block ciphers designed by James Massey for implementation in software and employing a 64-bit block. SAFER K-64, published in 1993, used a 64-bit key and SAFER K-128, published in 1994, employed a 128-bit key. After weaknesses were found, new versions were released called SAFER SK-40, SK-64, and SK-128, using 40- 64- and 128-bit keys, respectively. SAFER+ (1998) used a 128-bit block and was an unsuccessful candidate for the AES project; SAFER++ (2000) was submitted to the NESSIE project.

    • SEED: A block cipher using 128-bit blocks and 128-bit keys. Developed by the Korea Information Security Agency (KISA) and adopted as a national standard encryption algorithm in South Korea. Also described in RFC 4269.

    • Serpent:Serpent is another of the AES finalist algorithms. Serpent supports 128- 192- or 256-bit keys and a block size of 128 bits, and is a 32-round substitution–permutation network operating on a block of four 32-bit words. The Serpent developers opted for a high security margin in the 21 Flying Images 2.0 crack serial keygen of the algorithm; they determined that 16 rounds would be sufficient against known attacks but require 32 rounds in an attempt to future-proof the algorithm.

    • SHACAL: SHACAL is a pair of block ciphers based upon the Secure Hash Algorithm Bootstrap Studio 5.8.3 Crack + License Key Full Version 2022 and the fact that SHA is, at heart, a compression algorithm. As a hash function, SHA repeatedly calls on a compression scheme to alter the state of the data blocks. While SHA (like other hash functions) is irreversible, the compression function can be used for encryption by maintaining appropriate state information. SHACAL-1 is based upon SHA-1 and uses a 160-bit block size while SHACAL-2 is based upon SHA-256 and employs a 256-bit block size; both support key sizes from 128 to 512 bits. SHACAL-2 is one of the NESSIE block ciphers.

    • Simon and Speck: Simon and Speck are a pair of lightweight block ciphers proposed by the NSA in 2013, designed for highly constrained software or hardware environments. (E.g., 21 Flying Images 2.0 crack serial keygen, per the specification, AES requires 2400 gate equivalents and these ciphers require less than 2000.) While both cipher families perform well in both hardware and software, Simon has been optimized for high performance on hardware devices and Speck for performance in software. Both are Feistel ciphers and support ten combinations of block and key size:

    • Skipjack: SKC scheme proposed, along with the Clipper chip, as part of the never-implemented Capstone project. Although the details of the algorithm were never made public, Skipjack was a block cipher using an 80-bit key and 32 iteration cycles per 64-bit block. Capstone, proposed by NIST and the NSA as a standard for public and government use, met with great resistance by the crypto community largely because the design of Skipjack was classified (coupled with the key escrow requirement of the Clipper chip).

    • SM4: Formerly called SMS4, SM4 is a 128-bit block cipher using 128-bit keys and 32 rounds to process a block. Garrys Mod Keys Steam crack serial keygen in 2006, SM4 is used in the Chinese National Standard for Wireless Local Area Network (LAN) Authentication and Privacy Infrastructure (WAPI). SM4 had been a proposed cipher for the Institute of Electrical and Electronics Engineers (IEEE) 802.11i standard on security mechanisms for wireless LANs, but has yet to be accepted by the IEEE or International Organization for Standardization (ISO). SM4 is described in SMS4 Encryption Algorithm for Wireless Networks (translated by Whitfield Diffie and George Ledin, 2008) and at the SM4 (cipher) page. SM4 is issued by the Chinese State Cryptographic Authority as GM/T 0002-2012: SM4 (2012).

    • Tiny Encryption Algorithm (TEA): A family of block ciphers developed by Roger Needham and David Wheeler. TEA was originally developed in 1994, 21 Flying Images 2.0 crack serial keygen, and employed a 128-bit key, 64-bit block, and 64 rounds of operation. To correct certain 21 Flying Images 2.0 crack serial keygen in TEA, eXtended TEA (XTEA), aka Block TEA, was released in 1997. To correct weaknesses in XTEA and add versatility, Corrected Block TEA (XXTEA) was published in 1998. XXTEA also uses a 128-bit key, but block size can be any multiple of 32-bit words (with a minimum block size of 64 bits, or two words) and the number of rounds is a function of the block size (~52+6*words), as shown in Table 1.

    • Block Size
      2n
      Key Size
      mn
      Word Size
      n
      Key Words
      m
      Rounds
      T
      326416432
      4872
      96
      243
      4
      36
      36
      6496
      128
      323
      4
      42
      44
      9696
      144
      482
      3
      52
      54
      128128
      192
      256
      642
      3
      4
      68
      69
      72
    • TWINE: Designed by engineers at NEC in 2011, TWINE is a lightweight, 64-bit block cipher supporting 80- and 128-bit keys. TWINE's design goals included maintaining a small footprint in a hardware implementation (i.e., fewer than 2,000 gate equivalents) and small memory consumption in a software implementation.

    Although not an SKC scheme, check out Section 5.17 about Shamir's Secret Sharing (SSS).

    There are several other references that describe interesting algorithms and even SKC codes dating back decades. Two that leap to mind are the Crypto Museum's Crypto List and John J.G. Savard's (albeit old) A Cryptographic Compendium page.

    3.2, 21 Flying Images 2.0 crack serial keygen. Public Key Cryptography

    Public key cryptography has been said to be the most significant new development in cryptography in the last 300-400 years. Modern PKC was first described publicly by Stanford University professor Martin Hellman and graduate student Whitfield Diffie in 1976, 21 Flying Images 2.0 crack serial keygen. Their paper described a two-key crypto system in which two parties could engage in a secure communication over a non-secure communications channel ArcGIS Pro Crack Free Download Archives having to share a secret key.

    PKC depends upon the existence of so-called one-way functions, or mathematical functions that are easy to compute whereas their inverse function is relatively difficult to compute. Let me give you two simple examples:

    1. Multiplication vs. factorization: Suppose you have two prime numbers, 3 and 7, and you need to calculate the product; it should take almost no time to calculate that value, which is 21. Now suppose, instead, that you have a number that is a product of two primes, 21, and you need FileViewPro 2021 Crack + Activation Key Latest Free Download determine those prime factors. You will eventually come up with the solution but whereas calculating the product took milliseconds, factoring will take longer. The problem becomes 21 Flying Images 2.0 crack serial keygen harder if we start with primes that have, say, 400 Cockos REAPER 6.30 Crack Full Version Download or so, because the product will have ~800 digits.
    2. Exponentiation vs. logarithms: Suppose you take the number 3 to the 6th power; 21 Flying Images 2.0 crack serial keygen, it is relatively easy to calculate 36 = 729. But if you start with the number 729 and need to determine the two integers, x and y so that logx 729 = y, it will take longer to find the two values.

    While the examples above are trivial, they do represent two of the functional pairs that are used with PKC; namely, the ease of multiplication and exponentiation versus the relative difficulty of factoring and calculating logarithms, respectively. The mathematical "trick" in PKC is to find a trap door in the one-way function so that the inverse calculation becomes easy given knowledge of some item of information.

    Generic PKC employs two keys that are mathematically related although knowledge of one key does not allow someone to easily determine the other key. One key is used to encrypt the plaintext and the other key is used to decrypt the ciphertext. The important point here is that it does not matter which key is applied first, but that both keys are required for the process to work (Figure 1B). Because a pair of keys are required, this approach is also called asymmetric cryptography.

    In PKC, one of the keys is designated the public key and may be advertised as widely as the owner wants. The other key is designated the private key and is never revealed to another party, 21 Flying Images 2.0 crack serial keygen. It is straight-forward to send messages under this scheme. Suppose Alice FL Studio 12 crack serial keygen to send Bob a message. Alice encrypts some information using Bob's public key; Bob decrypts the ciphertext using his private key. This method could be also used to prove who sent a message; Alice, for example, could encrypt some plaintext with her private key; when Bob decrypts using Alice's public key, he knows that Alice sent the message (authentication) and Alice cannot deny having sent the message (non-repudiation).

    Public key cryptography algorithms that are in use today for key exchange or digital signatures include:

    • RSA: The first, and still most common, PKC implementation, named for the three MIT mathematicians who developed it — Ronald Rivest, Adi Shamir, and Leonard Adleman. RSA today is used in hundreds of software products and can be used for key exchange, digital signatures, or encryption of small blocks of data. RSA uses a variable size encryption block and a variable size key. The key-pair is derived from a very large number, n, that is the product of two prime numbers chosen according to special rules; these primes may be 100 or more digits in length each, yielding an n with roughly twice as many digits as the prime factors. The public key information includes n and a derivative of one of the factors of n; an attacker cannot determine the prime factors of n (and, therefore, the private key) from this information alone and that is what makes the RSA algorithm so secure. (Some descriptions of PKC erroneously state that RSA's safety is due to the difficulty in factoring large prime numbers. In fact, large prime numbers, like small prime numbers, only have two factors!) The ability for computers to factor large numbers, and therefore attack schemes such as RSA, is rapidly improving and systems today can find the prime factors of numbers with more than 200 digits. Nevertheless, if a large number is created from two prime factors that are roughly the same size, there is no known factorization algorithm that will solve the problem in a reasonable amount of time; a 2005 test to factor a 200-digit number took 1.5 years and over 50 years of compute time. In 2009, Kleinjung et al. reported that factoring a 768-bit (232-digit) RSA-768 modulus utilizing hundreds of systems took two years and they estimated that a 1024-bit RSA modulus would take about a thousand times as long. Even so, they suggested that 1024-bit RSA be phased out by 2013. (See the Wikipedia article on integer factorization.) Regardless, one presumed protection of RSA is that users can easily increase the key size to always stay ahead of the computer processing curve. As an aside, the patent for RSA expired in September 2000 which does not appear to have affected RSA's popularity one way or the other. A detailed example of RSA is presented below in Section 5.3.

    • Diffie-Hellman: After the RSA algorithm was published, Diffie and Hellman came up with their own algorithm. Diffie-Hellman is used for secret-key key exchange only, and not for authentication or digital signatures. More detail about Diffie-Hellman can be found below in Section 5.2.

    • Digital Signature Algorithm (DSA): The algorithm specified in NIST's Digital Signature Standard (DSS), provides digital signature capability for the authentication of messages. Described in FIPS PUB 186-4.

    • ElGamal: Designed by Taher Elgamal, ElGamal is a PKC system similar to Diffie-Hellman and used for key exchange. ElGamal is used in some later version of Pretty Good Privacy (PGP) as well as GNU Privacy Guard (GPG) and other cryptosystems.

    • Elliptic Curve Cryptography (ECC): A PKC algorithm based upon elliptic curves. ECC can offer levels of security with small keys comparable to RSA and other PKC methods. It was designed for devices with limited compute power and/or memory, 21 Flying Images 2.0 crack serial keygen, such as smartcards and PDAs. More detail about ECC can be found below in Section 5.8. Other references include the Elliptic Curve Cryptography page and the Online ECC Tutorial page, both from Certicom. See also RFC 6090 for a review of fundamental ECC algorithms and The Elliptic Curve Digital Signature Algorithm (ECDSA) for details about the use of ECC for digital signatures.

    • Identity-Based Encryption (IBE): IBE is a novel scheme first proposed by Adi Shamir in 1984. It is a PKC-based key authentication system where the public key can be derived from some unique information based upon the user's identity, allowing two users to exchange encrypted messages without having an a priori relationship. In Mini Golf Gold crack serial keygen, Dan Boneh (Stanford) and Matt Franklin (U.C., Davis) developed a practical implementation of IBE based on elliptic curves and a mathematical construct called the Weil Pairing. In that year, Clifford Cocks (GCHQ) also described another IBE solution based on quadratic residues in composite 21 Flying Images 2.0 crack serial keygen. RFC 5091: Identity-Based Cryptography Standard (IBCS) #1 describes an implementation of IBE using Boneh-Franklin (BF) and Boneh-Boyen (BB1) Identity-based Encryption. More detail about Identity-Based Encryption can be found below 21 Flying Images 2.0 crack serial keygen Section 5.16.

    • Public Key Cryptography Standards (PKCS): A set of interoperable standards and guidelines for public key cryptography, designed by RSA Data Security Inc. (These documents are no longer easily available; all links in this section are from archive.org.)

    • Cramer-Shoup: A public key cryptosystem proposed by R. Cramer and V. Shoup of IBM in 1998.

    • Key Exchange Algorithm (KEA): A variation on Diffie-Hellman; proposed as the key exchange method for the NIST/NSA Capstone project.

    • LUC: A public key cryptosystem designed by P.J. Smith and based on Lucas sequences, 21 Flying Images 2.0 crack serial keygen. Can be used for encryption and signatures, using integer factoring.

    • McEliece: A public key cryptosystem based on algebraic coding theory.

    For 21 Flying Images 2.0 crack serial keygen information on PKC algorithms, see "Public Key Encryption" (Chapter 8) in Handbook of Applied Cryptography, by A. Menezes, P. van Oorschot, and S. Vanstone (CRC Press, 1996).


    A digression: Who invented PKC? I tried to be careful in the first paragraph of this section to state that Diffie and Hellman "first described publicly" a PKC scheme. Although I have categorized PKC as a two-key system, that has been merely for convenience; the real criteria for a PKC scheme is 21 Flying Images 2.0 crack serial keygen it allows two parties to exchange a secret even though the communication with the shared secret might be overheard. There seems to be no question that Diffie and Hellman were first to publish; their method is described in the classic paper, "New Directions in Cryptography," published in the November 1976 issue of IEEE Transactions on Information Theory (IT-22(6), 644-654). As shown in Section 5.2, Diffie-Hellman uses the idea that finding Wondershare democreator 5.1 keygen,serial,crack,generator is relatively harder than performing exponentiation. And, indeed, it is the precursor to modern PKC which does employ two keys. Rivest, Shamir, and Adleman described an implementation that extended this idea in their paper, "A Method for Obtaining Digital Signatures and Public Key Cryptosystems," published in Mirillis Action! 4.21.2 Full Version With Crack Download February 1978 issue of the Communications of the ACM (CACM), (21(2), 120-126). Their method, of course, is based upon the relative ease of finding the product of two large prime numbers compared to finding the prime factors of a large number.

    Diffie and Hellman (and other sources) credit Ralph Merkle with first describing a public key distribution system that allows two parties to share a secret, although it was not a two-key system, per se. A Merkle Puzzle works where Alice creates a large number of encrypted keys, sends them all to Bob so that Bob chooses one at random and then lets Alice know which he has selected. An eavesdropper (Eve) will see all of the keys but can't learn which key Bob has selected (because he has encrypted the response with the chosen key). In this case, Eve's effort to break in is the square of the effort of Bob to choose a key. While this difference may be small it is often sufficient. Merkle apparently took a computer science course at UC Berkeley in 1974 and described his method, but had difficulty making people understand it; frustrated, he dropped the course. Meanwhile, he submitted the paper "Secure Communication Over Insecure Channels," which was published in the CACM in April 1978; Rivest et al.'s paper even makes reference to it. Merkle's method certainly wasn't published first, but he is often credited to have had the idea first.

    An interesting question, maybe, but who really knows? For some time, 21 Flying Images 2.0 crack serial keygen, it was a quiet secret that a team at the UK's Government Communications Headquarters (GCHQ) had first developed PKC in the early 1970s. Because of the nature of the work, GCHQ kept the original memos classified. In 1997, however, the GCHQ changed their posture when they realized that there was nothing to gain by continued silence. Documents show that a GCHQ mathematician named James Ellis started research into the key distribution problem in 1969 and that by 1975, James Ellis, Clifford Cocks, and Malcolm Williamson had worked out all of the fundamental details of PKC, yet couldn't talk about their work. (They were, of course, barred from challenging the RSA patent!) By 1999, Ellis, Cocks, and Williamson began to get their due credit in a break-through article in WIRED Magazine. And the National Security Agency (NSA) claims to have knowledge of this type of algorithm as early as 1966. For some additional insight on who knew what when, see Steve Bellovin's "The Prehistory of Public Key Cryptography."


    3.3. Hash Functions

    Hash functions, also called message digests and one-way encryption, are algorithms that, in essence, use no key (Figure 1C). Instead, a fixed-length hash value is computed based upon the plaintext that makes it impossible for either the contents or length of the plaintext to 21 Flying Images 2.0 crack serial keygen recovered. Hash algorithms are typically used to provide a digital fingerprint of a file's contents, often used to ensure that the file has not been altered by an intruder or virus, 21 Flying Images 2.0 crack serial keygen. Hash functions are also commonly employed by many operating systems to encrypt passwords. Hash functions, then, provide a mechanism to ensure the integrity of a file.

    Hash functions are also designed so that small changes in the input produce significant differences in the hash value, for example:

    Hash string 1: The quick brown fox jumps over the lazy dog
    Hash string 2: The quick brown fox jumps over the lazy dog.

    MD5 [hash string 1] = 37c4b87edffc5d198ff5a185cee7ee09
    MD5 [hash string 2] = 0d7006cd055e94cf614587e1d2ae0c8e

    SHA1 [hash string 1] = be417768b5c3c5c1d9bcb2e7c119196dd76b5570
    SHA1 [hash string 2] = 9c04cd6372077e9b11f70ca111c9807dc7137e4b

    RIPEMD160 [hash string 1] = ee061f0400729d0095695da9e2c95168326610ff
    RIPEMD160 [hash string 2] = 99b90925a0116c302984211dbe25b5343be9059e


    Let me reiterate that hashes are one-way encryption. You cannot take a hash and "decrypt" it to find the original string that created it, despite the many web sites that claim or suggest otherwise, such as CrackStation, Hashes.com, MD5 Online, md5thiscracker, OnlineHashCrack, and RainbowCrack.

    Note that these sites search databases and/or use rainbow tables to find a suitable string that produces the hash in question but one can't definitively guarantee what string originally produced the hash. This is an important distinction. Suppose that you want to crack someone's password, where the hash of the password is stored on the server. Indeed, all you then need is a string that produces the correct hash and you're in! However, you cannot prove that you have discovered the user's password, only a "duplicate key."


    Hash algorithms in common use today include:

    • Message Digest (MD) algorithms: A series of byte-oriented algorithms that produce a 128-bit hash value from an arbitrary-length message.

      • MD2 (RFC 1319): Designed for systems with limited memory, such as smart cards. (MD2 has been relegated to historical status, per RFC 6149.)

      • MD4 (RFC 1320): Developed by Rivest, similar to MD2 but designed specifically for fast processing in software. (MD4 has been relegated to historical status, per RFC 6150.)

      • MD5 (RFC 1321): Also developed by Rivest after potential weaknesses were reported in MD4; this scheme is similar to MD4 but is slower because more manipulation is made to the original data. MD5 has been implemented in a large number of products although several weaknesses in the algorithm were demonstrated by German cryptographer Hans Dobbertin in 1996 ("Cryptanalysis of MD5 Compress"). (Updated security considerations for MD5 can be found in RFC 6151.)

    • Secure 21 Flying Images 2.0 crack serial keygen Algorithm (SHA): Algorithm for NIST's Secure Hash Standard (SHS), 21 Flying Images 2.0 crack serial keygen, described in FIPS PUB 180-4 The status of NIST hash algorithms can be found on their "Policy on Hash Functions" page, 21 Flying Images 2.0 crack serial keygen.

      • SHA-1 produces a 160-bit hash value and was originally published as FIPS PUB 180-1 and RFC 3174. SHA-1 was deprecated by NIST as of the end of 2013 although it is still widely used.

      • SHA-2, originally described in FIPS PUB 180-2 and eventually replaced by FIPS PUB 180-3 (and FIPS PUB 180-4), comprises five algorithms in the SHS: SHA-1 plus SHA-224, SHA-256, SHA-384, and SHA-512 which can produce hash values that are 224, 256, 384, or 512 bits in length, respectively. SHA-2 recommends use of SHA-1, SHA-224, and SHA-256 for messages less than 264 bits in length, and employs a 512 bit block size; SHA-384 and SHA-512 are recommended for messages less than 2128 bits in length, and employs a 1,024 bit block size. FIPS PUB 180-4 also introduces the concept of a truncated hash in SHA-512/t, a generic name referring to a hash value based upon the SHA-512 algorithm that has been truncated to t bits; SHA-512/224 and SHA-512/256 are specifically described. SHA-224, -256, -384, and -512 are also described in RFC 4634.

      • SHA-3 is the current SHS algorithm. Although there had not been any successful attacks on SHA-2, NIST decided that having an alternative to SHA-2 using a different algorithm would be prudent. In 2007, they launched a SHA-3 Competition to find that alternative; a list of submissions can be found at The SHA-3 Zoo. In 2012, NIST announced that after reviewing 64 submissions, the winner was Keccak (pronounced "catch-ack"), a family of hash algorithms based on sponge functions. The NIST version can support hash output sizes of 256 and 512 bits.

    • RIPEMD: A series of message digests that initially came from the RIPE (RACE Integrity Primitives Evaluation) project. RIPEMD-160 was designed by Hans Dobbertin, Antoon Bosselaers, and Bart Preneel, and optimized for 32-bit processors to replace the then-current 128-bit hash functions. Other versions include RIPEMD-256, RIPEMD-320, 21 Flying Images 2.0 crack serial keygen, and RIPEMD-128.

    • eD2k: Named for the EDonkey2000 Network (eD2K), the eD2k hash is a root hash of an MD4 hash list of a given file. A root hash is used on peer-to-peer file transfer networks, where a file is broken into chunks; each chunk has its own MD4 hash associated with it and the server maintains a file that contains the hash list of all of the chunks. The root hash is the hash of the hash list file.

    • HAVAL (HAsh of VAriable Length): Designed by Y. Zheng, J. Pieprzyk and J. Seberry, a hash algorithm with many levels of security. HAVAL can create hash values that are 128, 21 Flying Images 2.0 crack serial keygen, 160, 192, 224, or 256 bits in length. More details can be found in "HAVAL - A one-way hashing algorithm with variable length output" by Zheng, Pieprzyk, and Seberry (AUSCRYPT '92).

    • The Skein Hash Function Family: The Skein Hash Function Family was proposed to NIST in their 2010 hash function competition. Skein is fast due to using just a few simple computational primitives, secure, and very flexible — per the specification, it can be used as a straight-forward hash, MAC, 21 Flying Images 2.0 crack serial keygen, HMAC, digital signature hash, 21 Flying Images 2.0 crack serial keygen, key derivation mechanism, stream cipher, or pseuo-random number generator. Skein supports internal state sizes of 256, 512 and 1024 bits, and arbitrary output lengths.

    • SM3: SM3 is a 256-bit hash function operating on 512-bit input blocks. Part of a Chinese National Standard, SM3 is issued by the Chinese State Cryptographic Authority as GM/T 0004-2012: SM3 cryptographic hash algorithm (2012) and GB/T 32905-2016: Information security techniques—SM3 cryptographic hash algorithm (2016). More information can also be found at the SM3 (hash function) page.

    • Tiger: Designed by Ross Anderson and Eli Biham, Tiger is designed to be secure, run efficiently on 64-bit processors, and easily replace MD4, MD5, SHA and SHA-1 in other applications. Tiger/192 produces a 192-bit output and is compatible with 64-bit architectures; Tiger/128 and Tiger/160 produce a hash of length 128 and 160 bits, respectively, to provide compatibility with the other hash functions mentioned above.

    • Whirlpool: Designed by V. Rijmen (co-inventor of Rijndael) and 21 Flying Images 2.0 crack serial keygen. Barreto, Whirlpool is one of two hash functions endorsed by the NESSIE competition (the other being SHA). Whirlpool operates on messages less than 2256 bits in length and produces a message digest of 512 bits. The design of this hash function is very different than that of MD5 and SHA-1, making it immune to the types of attacks that succeeded on those hashes.

    Readers might be interested in HashCalc, a Windows-based program that calculates hash values using a dozen algorithms, including MD5, SHA-1 and several variants, RIPEMD-160, and Tiger. Command line utilities that calculate 21 Flying Images 2.0 crack serial keygen values include sha_verify by Dan Mares (Windows; supports MD5, SHA-1, SHA-2) and md5deep (cross-platform; supports MD5, SHA-1, SHA-256, Tiger, and Whirlpool).


    A digression on hash collisions. Hash functions are sometimes misunderstood and some sources claim that no two files can 21 Flying Images 2.0 crack serial keygen the same hash value. This is in theory, if not in fact, incorrect. Consider a hash function that provides a 128-bit hash value. There are, then, 2128 possible hash values, 21 Flying Images 2.0 crack serial keygen. But there are an infinite number of possible files and ∞ >> 2128. Therefore, there have to be multiple files — in fact, there have to be an infinite number of files! — that have the same 128-bit hash value. pdf xchange pro serial number Archives - Patch Cracks, while even this is theoretically correct, it is not true in practice because hash algorithms are designed to work with a limited 21 Flying Images 2.0 crack serial keygen size, as mentioned above, 21 Flying Images 2.0 crack serial keygen. For example, SHA-1, SHA-224, and SHA-256 produce hash values that are 160, 224, and 256 bits in length, respectively, and limit the message length to less than 264 bits; SHA-384 and all SHA-256 variants limit the message length to less than 2128 bits. Nevertheless, hopefully you get my point — and, alas, even if you don't, do know that there are multiple files that have the same MD5 or SHA-1 hash values.)

    The difficulty is not necessarily in finding two files with the same hash, but in finding a second file that has the same hash value as a given first file. Consider this example. A human head has, generally, no more than ~150,000 hairs. Since there are more than 7 billion people on earth, we know that there are a lot of people with the same number of hairs on their head. Finding two people with the same number of hairs, then, 21 Flying Images 2.0 crack serial keygen, would be relatively simple. The harder problem is choosing one person (say, you, the reader) and then finding another person who has the same number of hairs on their head as you have on yours.

    This is somewhat similar to the Birthday Problem. We know from probability that if you choose a random group of ~23 people, the probability is about 50% that two will share a birthday (the probability goes up to 99.9% with a group of 70 people). However, if you randomly select one person in a group of 23 and try to find a match to that person, the probability is only about 6% of finding a match; you'd need a group of 253 for a 50% probability of a shared birthday to one of the people chosen at random (and a group of more than 4,000 to obtain a 99.9% probability).

    What is hard to do, then, is to try to create a file that matches a given hash value so as 21 Flying Images 2.0 crack serial keygen force a hash value collision — which is the reason that hash functions are used extensively for information security and computer forensics applications. Alas, researchers as far back as 2004 found that practical collision attacks 21 Flying Images 2.0 crack serial keygen be launched on MD5, SHA-1, and other hash algorithms and, today, it is generally recognized that MD5 and SHA-1 are pretty much broken. Readers interested in this problem should read the following:

    • AccessData. (2006, April). MD5 Collisions: The Effect on Computer Forensics. AccessData White Paper.
    • Burr, W. (2006, March/April). Cryptographic hash standards: Where do we go from here?IEEE Security & Privacy, 21 Flying Images 2.0 crack serial keygen, 4(2), 88-91.
    • Dwyer, D. (2009, June 3). SHA-1 Collision Attacks Now 252. SecureWorks Research blog.
    • Gutman, P., Naccache, D., & Palmer, C.C. 21 Flying Images 2.0 crack serial keygen, May/June). When hashes collide. IEEE Security & Privacy, 3(3), 68-71.
    • Kessler, G.C. (2016). The Impact of MD5 File Hash Collisions on Digital Forensic Imaging. Journal of Digital Forensics, Security & Law, 11(4), 129-138.
    • Kessler, G.C. (2016). The Impact of SHA-1 File Hash Collisions on Digital Forensic Imaging: A Follow-Up Experiment. Journal of Digital Forensics, Security & Law, 11(4), 139-148.
    • Klima, V. (2005, March). Finding MD5 Collisions - a Toy For a Notebook.
    • Lee, R. (2009, January 7). Law Is Not A Science: Admissibility of Computer Evidence and MD5 Hashes. SANS Computer Forensics blog.
    • Leurent, G. & Peyrin, 21 Flying Images 2.0 crack serial keygen, T. (2020, January). SHA-1 is a Shambles: First Chosen-Prefix Collision on SHA-1 and Application to the PGP Web of Trust. Real World Crypto 2020.
    • Leurent, G. & Peyrin, T. (2020, January). SHA-1 is a Shambles: First Chosen-Prefix Collision on SHA-1 and Application to the PGP Web of Trust.(paper)
    • Stevens, M., Bursztein, E., Karpman, P., Albertini, A., & 21 Flying Images 2.0 crack serial keygen, Y. (2017). The first collision for full SHA-1.
    • Stevens, M., Karpman, P., & Peyrin, T. (2015, October 8). Freestart collision on full SHA-1. Cryptology ePrint Archive, Report 2015/967.
    • Thompson, 21 Flying Images 2.0 crack serial keygen, E. (2005, February). MD5 collisions and the impact on computer forensics. Digital Investigation, 2(1), 36-40.
    • Wang, X., Feng, D., Lai, X., & Yu, H. (2004, August). Collisions for Hash Functions MD4, MD5, HAVAL-128 and RIPEMD.
    • Wang, X., Yin, Y.L., & Yu, H. (2005, February 13). Collision Search Attacks on SHA1.

    Readers are also referred to the Eindhoven University of Technology HashClash Project Web site. for For additional information on hash functions, see David Hopwood's MessageDigest Algorithms page and Peter Selinger's MD5 Collision Demo page. For historical purposes, take a look at the situation with hash collisions, circa 2005, in RFC 4270.

    In October 2015, the SHA-1 Freestart Collision was announced; see a report by Bruce Schneier and the developers of the attack (as well as the paper above by Stevens et al. (2015)). In February 2017, the first SHA-1 collision was announced on the Google Security Blog and Centrum Wiskunde & Informatica's Shattered page. See also the paper by Stevens et al. (2017), listed above. If ths isn't enough, see the SHA-1 is a Shambles Web page and the Leurent & Peyrin paper, 21 Flying Images 2.0 crack serial keygen, listed above.

    For an interesting twist on this discussion, read about the Nostradamus attack reported at Predicting the winner of the 2008 US Presidential Elections using a Sony PlayStation 3 (by M. Stevens, A.K. Lenstra, and B. de Weger, November 2007).


    Finally, note that certain extensions of hash functions are used for a variety of information security and digital forensics applications, such as:

    • Hash libraries, aka hashsets, are sets of hash values corresponding 21 Flying Images 2.0 crack serial keygen known files. A hashset containing the hash values of all files known to be a part of a given operating system, for example, could form a set of known good files, and could be ignored in an investigation for malware or other suspicious file, whereas as hash library of known child pornographic images could form a set of known bad files and be the target 21 Flying Images 2.0 crack serial keygen such an investigation.
    • Rolling hashes refer to a set of hash values that are computed based upon a fixed-length "sliding window" through the input. As an example, a hash value might be computed on bytes 1-10 of a file, then on bytes 2-11, 3-12, 4-13, etc.
    • Fuzzy hashes are an area of intense research and represent hash values that represent two inputs that are similar, 21 Flying Images 2.0 crack serial keygen. Fuzzy hashes are used to detect documents, images, or other files that are close to each other with respect to content. See "Fuzzy Hashing" by Jesse Kornblum for a good treatment of this topic.

    3.4. Why Three Encryption Techniques?

    So, why are there so many different types of cryptographic schemes? Why can't we do everything we need with just one?

    The answer is that each scheme is optimized for some specific cryptographic application(s). Hash functions, for example, are well-suited for ensuring data integrity because any change made to the contents of a message will result in the receiver calculating a different hash value than the one placed in the transmission by the sender. Since it is highly unlikely that two different messages will yield the same hash 21 Flying Images 2.0 crack serial keygen, data integrity is ensured to a EaseUS Data Recovery Wizard 12.9 Crack Full Version Download degree of confidence.

    Secret key cryptography, on the other hand, is ideally suited to encrypting messages, thus providing privacy and confidentiality. The sender can generate a session key on a per-message basis to encrypt the message; the receiver, of course, needs the same session key in order to decrypt the message.

    Key exchange, of course, is a key application of public key cryptography (no pun intended). Asymmetric schemes can also be used for non-repudiation and user authentication; if the receiver can obtain the session key encrypted with the sender's private key, then only this sender could have sent the message. Public key cryptography could, theoretically, also be used to encrypt messages although this is rarely done 21 Flying Images 2.0 crack serial keygen secret key cryptography values can generally be computed about 1000 times faster than public key cryptography values.

    FIGURE 4: Use of the three cryptographic techniques for secure communication.


    Figure 4 puts all of this together and shows how a hybrid cryptographic scheme combines all of these functions to form a secure transmission comprising a digital signature and digital envelope. In this example, the sender of the message is Alice and the receiver is Bob.

    A digital envelope comprises an encrypted message and an encrypted session key. Alice uses secret key cryptography to encrypt her message using the session key, which she generates at random with each session. Alice then encrypts the session key using Bob's public key. The encrypted message and encrypted session key together form the digital envelope. Upon receipt, Bob recovers the session secret key using his private key and then decrypts the 21 Flying Images 2.0 crack serial keygen message.

    The digital signature is formed in two steps. First, Alice computes the hash value of her message; next, she encrypts the hash value with her private key. Upon receipt of the digital signature, Bob recovers the hash value calculated by Alice by decrypting the digital signature with Alice's public key. Bob can then apply the hash function to Alice's original message, which he has already decrypted (see previous paragraph). If the resultant hash value is not the same as the value supplied by Alice, then Bob knows that the message has been altered; if the hash values are the same, Bob should believe that the message he received is identical to the one that Alice sent.

    This scheme also provides nonrepudiation since it proves that Alice sent the message; if the hash value recovered by Bob using Alice's public key proves that the message has not been altered, then only Alice could have created the digital signature. Bob also has proof that he is the intended receiver; if he can correctly decrypt the message, then he must have correctly decrypted the session key meaning that his is the correct private key.

    This diagram purposely suggests a cryptosystem where the session key is used for just a single session. Even if this session key is somehow broken, only this session will be compromised; the session key for the next session is not based upon the key for this session, just as this session's key was not dependent on the key from the previous session. This is known as Perfect Forward Secrecy; you might lose one session key due to a compromise but you won't lose all of them. (This was an issue in the 2014 OpenSSL vulnerability known as Heartbleed.)

    3.5. The Significance of Key Length

    In a 1998 article in the industry literature, a writer made the claim that 56-bit keys did not provide as adequate protection for DES at that time 21 Flying Images 2.0 crack serial keygen they did in 1975 because computers were 1000 times faster in 1998 than in 1975. Therefore, the writer went on, we needed 56,000-bit keys in 1998 instead of 56-bit keys to provide adequate protection. The conclusion was then drawn that because 56,000-bit keys are infeasible (true), we should accept the fact that we have to live with weak cryptography (false!). The major error here is that the writer did not take into account that the number of possible key values double whenever a single bit is added to the key length; 21 Flying Images 2.0 crack serial keygen, Betternet VPN Premium [6.12.1] Full Version + Crack (Latest 2021) Download 57-bit key has twice as many values as a 56-bit key (because 257 is two times 256). In fact, a 66-bit key would have 1024 times more values than a 56-bit key.

    But this does bring up the question — "What is the significance of key length as it affects the level of protection?"

    In cryptography, size does matter. The larger the key, the harder it is to crack a block of encrypted data. The reason that large keys offer more protection is almost obvious; computers have made it easier to attack ciphertext by using brute force methods rather than by attacking the mathematics (which are generally well-known anyway). With a brute force attack, the attacker merely generates every possible key and applies it to the ciphertext. Any resulting plaintext that makes sense offers a candidate for a legitimate key, 21 Flying Images 2.0 crack serial keygen. This was the basis, of course, of the EFF's attack on DES.

    Until the mid-1990s or so, brute force attacks were beyond the capabilities of computers that were within the budget of the attacker community. By that time, however, significant compute power was typically available and accessible. General-purpose computers such as PCs were already being used for brute force attacks. For serious attackers with money to spend, such as some large companies or governments, Field Programmable Gate Array (FPGA) or Application-Specific Integrated Circuits (ASIC) technology offered the ability to build specialized chips that could provide even faster and cheaper solutions than a PC. As an example, the AT&T Optimized Reconfigurable Cell Array (ORCA) FPGA chip cost about $200 and could test 30 million DES keys per second, while a $10 ASIC chip could test 200 million DES keys per second; compare that to a PC which might be able to test 40,000 keys per second. Distributed attacks, harnessing the power of up to tens of thousands of powerful CPUs, are now commonly employed to try to brute-force crypto keys.

    Type of AttackerBudgetToolTime and Cost
    Per Key Recovered
    Key Length Needed
    For Protection
    In Late-1995
    40 bits56 bits
    Pedestrian HackerTinyScavenged
    computer
    time
    1 weekInfeasible45
    $400FPGA5 hours
    ($0.08)
    38 years
    ($5,000)
    50
    Small Business$10,000FPGA12 minutes
    ($0.08)
    18 months
    ($5,000)
    55
    Corporate Department$300KFPGA24 seconds
    ($0.08)
    19 days
    ($5,000)
    60
    ASIC0.18 seconds
    ($0.001)
    3 hours
    ($38)
    Big Company$10MFPGA7 seconds
    ($0.08)
    13 hours
    ($5,000)
    70
    ASIC0.005 seconds
    ($0.001)
    6 minutes
    ($38)
    Intelligence Agency$300MASIC0.0002 Rosetta Stone Crack Archives seconds
    ($38)
    75

    Table 2 — from a 1996 article discussing both why exporting 40-bit keys was, in essence, no crypto at all 21 Flying Images 2.0 crack serial keygen why DES' days were numbered — shows what DES key sizes were needed to protect data from attackers with different time and financial resources. This information was not merely academic; one of the basic tenets of any security system is to have an idea of what you are protecting and from whom are you protecting it! The table clearly shows that a 40-bit key was essentially worthless against even the most unsophisticated attacker. On the other hand, 56-bit keys were fairly strong unless you might be subject to some pretty serious corporate or government espionage. But note that even 56-bit keys were clearly on the decline in their value and that the times in the table were worst cases.

    So, how big is big enough? DES, invented in 1975, was still in use at the turn of the century, nearly 25 years later. If we take that to be a design criteria (i.e., a 20-plus year lifetime) and we believe Moore's Law ("computing power doubles every 18 months"), then a key size extension of 14 bits (i.e., a factor of more than 16,000) should be adequate. The 1975 DES proposal suggested 56-bit keys; by 1995, a 70-bit key would have been required to offer equal protection and an 85-bit key necessary by 2015.

    A 256- or 512-bit SKC key will probably suffice for some time because that length keeps us ahead of the brute force capabilities of the attackers. Note that while a large key is good, a huge key may not always be better; for example, expanding PKC keys beyond the current 2048- or 4096-bit lengths doesn't add any necessary protection at this time. Weaknesses in cryptosystems are largely based upon key management rather than weak keys.

    Much of the discussion above, including the table, is based on the paper "Minimal Key Lengths for Symmetric Ciphers to Provide Adequate Commercial Security" by M. Blaze, W. Diffie, R.L. Rivest, B. Schneier, T. Shimomura, E. Thompson, and M. Wiener (1996).

    The most effective large-number factoring methods today use a mathematical Number Field Sieve to find a certain number of relationships and then uses a matrix operation to solve a linear equation to produce the two prime factors. The sieve step actually involves a large number of operations that can be performed in parallel; solving the linear equation, however, requires a supercomputer. Indeed, finding the solution to the RSA-140 challenge in February 1999 — factoring a 140-digit (465-bit) prime number — required 200 computers across the Internet about 4 weeks for the first step and a Cray computer 100 hours and 810 MB of memory to do the second step.

    In early 1999, Shamir (of RSA fame) described a new machine that could increase factorization speed by 2-3 orders of magnitude. Although no detailed plans were provided nor is one known to have been built, the concepts of TWINKLE (The Weizmann Institute Key Locating Engine) could result in a specialized piece of hardware that would cost about $5000 and have the processing power of 100-1000 PCs. There still appear to be many engineering details that have to be worked out before such a machine could be built. Furthermore, the hardware improves the sieve step only; the matrix operation is not optimized at all by this design and the complexity of this step grows rapidly with key length, both in terms of processing time and memory requirements. Nevertheless, this plan conceptually puts 512-bit keys within reach of being factored. Although most PKC schemes allow keys that are 1024 bits and longer, Shamir claims that 512-bit RSA keys "protect 95% of today's E-commerce on the Internet." (See Bruce Schneier's Crypto-Gram (May 15, 1999) for more information.)

    It is also interesting to note that while cryptography is good and strong cryptography is better, long keys may disrupt the nature of the randomness of data files. Shamir and van Someren ("Playing hide and seek with stored keys") have noted that a new generation of viruses can be written that will find files encrypted with 21 Flying Images 2.0 crack serial keygen keys, making them easier to find by intruders and, therefore, more prone to attack.

    Finally, U.S. government policy has tightly controlled the export of crypto products since World War II. Until the mid-1990s, export outside of North America of cryptographic products using keys greater than 40 bits in length was prohibited, which made those products essentially worthless in the marketplace, particularly for electronic commerce; today, crypto products are widely 21 Flying Images 2.0 crack serial keygen on the Internet without restriction. The U.S. Department of Commerce Bureau of Industry and Security maintains an Encryption FAQ web page with more information about the current state of encryption registration.


    Without meaning to editorialize too much in this tutorial, a bit of historical context might be helpful. In the mid-1990s, the U.S, 21 Flying Images 2.0 crack serial keygen. Department of Commerce still classified cryptography as a munition and limited the export of any products that contained crypto. For that reason, browsers in the 1995 era, such as Internet Explorer and Netscape, had a domestic version with 21 Flying Images 2.0 crack serial keygen encryption (downloadable only in the U.S.) and an export version with 40-bit encryption. Many cryptographers felt that the export limitations should be 21 Flying Images 2.0 crack serial keygen because they only applied to U.S. products and seemed to have been put 21 Flying Images 2.0 crack serial keygen place by policy makers who believed that only the U.S. knew how to build strong crypto algorithms, ignoring the work ongoing in Australia, Canada, Israel, South Africa, the U.K., and other locations in the 1990s. Those restrictions were lifted by 1996 or 1997, but there is still a prevailing attitude, apparently, that U.S. crypto algorithms are the only strong ones around; consider Bruce Schneier's blog in June 2016 titled "CIA Director John Brennan Pretends Foreign Cryptography Doesn't Exist." Cryptography is a decidedly international game today; note the many countries mentioned above as having developed various algorithms, not the least of which is the fact that NIST's Advanced Encryption Standard employs an algorithm submitted by cryptographers from Belgium. For more evidence, see Schneier's Worldwide Encryption Products Survey (February 2016).


    On a related topic, public key crypto schemes can be used for several purposes, 21 Flying Images 2.0 crack serial keygen, including key exchange, digital signatures, authentication, and more. In those PKC systems used for SKC key exchange, the PKC key lengths are chosen so as to be resistant to some selected level of attack. The length of the secret keys exchanged via that system have to have at least the same level of attack resistance. Thus, the three parameters of such a system — system strength, secret key strength, and public key strength — must be matched. This topic is explored in more detail in Determining Strengths For Public Keys Used For Exchanging Symmetric Keys (RFC 3766).

    4. TRUST MODELS

    Secure 21 Flying Images 2.0 crack serial keygen of cryptography requires trust. While secret key cryptography can ensure message confidentiality and hash codes can ensure integrity, none of this works without trust, 21 Flying Images 2.0 crack serial keygen. In SKC, Alice and Bob had to share a secret key. PKC solved the secret distribution problem, but how does Alice really know that Bob is who he 21 Flying Images 2.0 crack serial keygen he is? Just because Bob has a public and private key, and purports to be "Bob," how does Alice know that a malicious person (Mallory) is not pretending to be Bob?

    There are a number of trust models employed by various cryptographic schemes. This section will explore three of them:

    • The web of trust employed by Pretty Good Privacy (PGP) users, who hold their own set of trusted public keys.
    • Kerberos, a secret key distribution scheme using a trusted third party.
    • Certificates, which allow a set of trusted third 21 Flying Images 2.0 crack serial keygen to authenticate each other and, by implication, each other's users.

    Each of these trust models differs in complexity, general applicability, scope, and scalability.

    4.1. PGP Web of Trust

    Pretty Good Privacy (described more below in Section 5.5) is a widely used private e-mail scheme based on public key methods. A PGP user maintains a local keyring of all their known and trusted public keys. The user makes their own determination about the trustworthiness of a key using what is called a "web of trust."

    FIGURE 5: GPG keychain.

    Figure 5 shows a PGP-formatted keychain from the GNU Privacy Guard (GPG) software, an implementation of the OpenPGP standard. This is a section of my keychain, so only includes public keys from individuals whom I know and, presumably, trust. Note that keys are associated with e-mail addresses rather than individual names.

    In general, the PGP Web of trust works as follows. Suppose that Alice needs Bob's public key. Alice could just ask Bob for it directly via e-mail or download the public key from a PGP key server; this server might a well-known PGP key repository or a site that Bob maintains himself. In fact, Bob's public key might be stored or listed in many places. (My public key, for example, can be found at https://www.garykessler.net/pubkey.html or at several public PGP key servers, including https://keys.openpgp.org.) Alice is prepared to believe that Bob's public key, as stored at these locations, is valid.

    Suppose Carol claims to hold Bob's public key and offers to give the key to Alice. How does Alice know that Carol's version of Bob's key is valid or if Carol is actually giving Alice a key that will allow Mallory access to messages? The answer is, "It depends." If Alice trusts Carol and Carol says that she thinks that her version of Bob's key is valid, then Alice may — at her option — trust that key. And trust is not necessarily transitive; if Dave has a copy of Bob's key and Carol trusts Dave, it does not necessarily follow that Alice trusts Dave even if she does trust Carol.

    The point here is that who Alice trusts and how she makes that determination is strictly up to Alice. PGP makes no statement and has no protocol about how one user determines whether Yaldex PopUp 3.0 crack serial keygen trust another user or not. In any case, encryption and signatures based on public keys can only be used when the appropriate public key is on the user's keyring.

    4.2. Kerberos

    Kerberos is a commonly used authentication scheme on the Internet. Developed by MIT's Project Athena, Kerberos is named for the three-headed dog who, according to Greek mythology, guards the entrance of Hades (rather than the exit, for some reason!).

    Kerberos employs a client/server architecture and provides user-to-server authentication rather than host-to-host authentication. In this model, security and authentication will be based on secret key technology where every host on the 21 Flying Images 2.0 crack serial keygen has its own secret key. It would clearly be unmanageable if every host had to know the keys of all other hosts so a secure, 21 Flying Images 2.0 crack serial keygen, trusted host somewhere on the network, known as a Key Distribution Center (KDC), knows the keys for all of the hosts (or at least some of the hosts within a portion of the network, called a realm). In this way, when a new node is brought online, only the KDC and the new node need to be configured with the node's key; keys can be distributed physically or by some other secure means.

    FIGURE 6: Kerberos architecture.


    The Kerberos Server/KDC has two main functions (Figure 6), known as the Authentication Server (AS) and Ticket-Granting Server (TGS). The steps in establishing an authenticated session between an application client and the application server are:
    1. The Kerberos client software establishes a connection with the Kerberos server's AS function. The AS first authenticates that the client is who it purports to be. The AS then provides the client with a secret key for this login session (the TGS session key) and a ticket-granting ticket (TGT), which gives the client permission to talk to the TGS. The ticket has a finite lifetime so that the 21 Flying Images 2.0 crack serial keygen process is repeated periodically.
    2. The client now communicates with the TGS to obtain the Application 21 Flying Images 2.0 crack serial keygen key so that it (the client) can establish a connection to the service it wants. The client supplies the TGS with the TGS session key and TGT; the TGS responds with an application session key (ASK) and an encrypted form of the Application Server's secret key; this secret key is never sent on 21 Flying Images 2.0 crack serial keygen network in 2Flyer Screensaver Builder Pro 6.1 crack serial keygen other form.
    3. The client has now authenticated itself AnyUnlock crack serial keygen can prove its identity to the Application Server by supplying the Kerberos ticket, application session key, and encrypted Application Server secret key. The Application Server responds with similarly encrypted information 21 Flying Images 2.0 crack serial keygen authenticate itself to the client. At this point, the client can initiate the intended service requests (e.g., Telnet, FTP, HTTP, or e-commerce transaction session establishment).

    The current version of this MikroTik 7.1 Crack Archives is Kerberos V5 (described in RFC 1510). While the details of their operation, functional capabilities, and message formats are different, the conceptual overview above pretty much holds for both. One primary difference is that Kerberos V4 uses only DES to generate keys and encrypt messages, while V5 allows other schemes to be employed (although DES is still the most widely algorithm used).

    4.3. Public Key Certificates and Certificate Authorities

    Certificates and Certificate Authorities (CA) are necessary for widespread use of cryptography for e-commerce applications. While a combination of secret and public key cryptography can solve the business issues discussed above, crypto cannot alone address the trust issues that must exist 21 Flying Images 2.0 crack serial keygen a customer and vendor in the very fluid, very dynamic e-commerce relationship. How, for example, does one site obtain another party's public key? How does a recipient determine if a public key really belongs to the sender? How does the recipient know that the sender is using their public key for a legitimate purpose for which they are authorized? When does a public key expire? How can a key be revoked in case of compromise or loss?

    The basic concept of a certificate is one that is familiar to all of us. A driver's license, credit card, or SCUBA certification, for example, identify us to others, indicate something that we are authorized to do, have an expiration date, and identify the authority that granted 21 Flying Images 2.0 crack serial keygen certificate.

    As complicated as this may sound, it really isn't. Consider driver's licenses. I have one issued by the State of Florida. The license establishes my identity, indicates the type of vehicles that I can operate and the fact that I must wear corrective lenses while doing so, identifies the issuing authority, and notes that I am an organ donor. When I drive in other states, the other jurisdictions throughout the U.S. recognize the authority of Florida to issue this "certificate" and they 21 Flying Images 2.0 crack serial keygen the information it contains. When I leave the U.S., everything changes. When I am in Aruba, Australia, Canada, Israel, and many other countries, they will accept not the Florida license, per se, but any license issued in the U.S. This analogy represents the certificate trust chain, where even certificates carry certificates.

    For purposes of electronic transactions, certificates are digital documents. The specific functions of the certificate include:

    • Establish identity: Associate, or bind, a public key to an individual, 21 Flying Images 2.0 crack serial keygen, organization, corporate position, or other entity.
    • Assign authority: Establish 21 Flying Images 2.0 crack serial keygen actions the holder may or may not take based upon this certificate.
    • Secure confidential information (e.g., encrypting the session's symmetric key for data confidentiality).

    Typically, a certificate contains a public key, a name, an expiration date, the name of the authority that issued the certificate (and, therefore, is vouching for the identity of the user), a serial number, any pertinent policies describing how the certificate was issued and/or how the certificate may be used, the digital signature of the certificate issuer, and perhaps other information.

    FIGURE 7: VeriSign Class 3 certificate.

    A sample abbreviated certificate is shown in Figure 7. This is a typical certificate found in a browser, in 21 Flying Images 2.0 crack serial keygen case, Mozilla Firefox (MacOS). While this is a certificate issued by VeriSign, many root-level certificates can be found shipped with browsers. When the browser makes a connection to a secure Web site, the Web server sends its public key certificate to the browser. The browser then checks the certificate's signature against the public key that it has stored; if there is a match, the certificate is taken as valid and the Web site verified by this Adguard crack serial keygen is considered to be "trusted."

    The most widely accepted certificate format is the one defined in International Telecommunication Union Telecommunication Standardization Sector (ITU-T) Recommendation X.509. Rec. X.509 is a specification used around the world and any applications complying with X.509 can share certificates. Most certificates today comply with X.509 Version 3 and contain the following information:

    • Version number
    • Certificate serial number
    • Signature algorithm identifier
    • Issuer's name and unique identifier
    • Validity (or operational) period
    • Subject's name and unique identifier
    • Subject public key information
    • Standard extensions
      • Certificate appropriate use definition
      • Key usage limitation definition
      • Certificate policy information
    • Other extensions
      • Application-specific
      • CA-specific

    Certificate authorities are the repositories for public keys and can be any agency that issues certificates. A company, for example, may issue certificates to its employees, a college/university to its students, a store to its customers, an Internet service provider to its users, or a government to its constituents.

    When a sender needs an intended receiver's public key, the sender must get that key from the receiver's CA. That scheme is straight-forward if the sender and receiver have certificates issued by the same CA. If not, how does the sender know to trust the foreign CA? One industry wag has noted, about trust: "You are either born with it or have it granted upon you." Thus, some CAs will be trusted because they are known to be reputable, such as the CAs operated by AT&T Services, Comodo, DigiCert (formerly GTE Cybertrust), EnTrust, Broadcom (formerly Symantec, formerly VeriSign), and Thawte. CAs, in turn, form trust relationships with other CAs. Thus, if a user queries a foreign CA for information, 21 Flying Images 2.0 crack serial keygen, the user may ask to see a list of CAs that establish a "chain of trust" back to the user.

    One major feature to look for in a CA is their identification policies and procedures. When a user generates a key pair and forwards the public key to a CA, the CA has to check the sender's identification and takes any steps necessary to assure itself that the request is really coming from the advertised sender. Different CAs have different identification 21 Flying Images 2.0 crack serial keygen and will, therefore, be trusted differently by other CAs. Verification of identity is just one of many issues that are part of a CA's Certification Practice Statement (CPS) and policies; other issues include how the CA protects the public keys in its care, how lost or compromised keys are revoked, and how the CA protects its own private keys.

    As a final note, CAs are not immune to attack and certificates themselves are able to be counterfeited, 21 Flying Images 2.0 crack serial keygen. One of the first such episodes occurred at the turn of the century; on January 29 and 30, 2001, two VeriSign Class 3 code-signing digital certificates were issued to an individual who fraudulently claimed to be a Microsoft employee (CERT/CC CA-2001-04 and Microsoft Security Bulletin MS01-017 - Critical). Problems have continued over the years; good write-ups on this can be found at "Another Certification Authority Breached (the 12th!)" and "How Cybercrime Exploits Digital Certificates." Readers are also urged to read "Certification Authorities Under Attack: A Plea for Certificate Legitimation" (Oppliger, R., January/February 2014, IEEE Internet Computing, 18(1), 40-47).

    As a partial way to address this issue, the Internet Security Research Group (ISRG) designed the Automated Certificate Management Environment (ACME) protocol. ACME is a communications protocol that streamlines the process of deploying a Public Key Infrastructure (PKI) by automating interactions between CAs and Web servers that wish to obtain a certificate. More information can be found at the Let's Encrypt Web site, an ACME-based CA service provided by the ISRG.

    4.4. Summary

    The paragraphs above describe three very different trust models. It is hard to say that any one is better than the others; it depends upon your application. One of the biggest and fastest growing applications of cryptography today, though, is electronic commerce (e-commerce), a term that itself begs for a formal definition.

    PGP's web of trust is easy to maintain and very much based on the reality of users as people. The model, however, is limited; just how many public keys can Hitman Pro 3.8.16 Crack Archives single user reliably store and maintain? And what if you are using the "wrong" computer when you want to send a message and can't access your keyring? How easy it is to revoke a key if 21 Flying Images 2.0 crack serial keygen is compromised? PGP may also not scale well to an e-commerce scenario of secure communication between total strangers on short-notice.

    Kerberos overcomes many of the problems of PGP's web of trust, in that it is scalable and its scope can be very large. However, it also requires that the Kerberos server have a priori knowledge of all client systems prior to any transactions, which makes it unfeasible for "hit-and-run" client/server relationships as seen in e-commerce.

    Certificates and the collection of CAs will form a PKI. In the early days of the Internet, every host had to maintain a list of every other host; the Domain Name System (DNS) introduced the idea of a distributed database for this purpose and the DNS is one of the key reasons that the Internet has grown as it has. A PKI will fill a similar 21 Flying Images 2.0 crack serial keygen in the e-commerce and PKC realm.

    While certificates and the benefits of a PKI are most often associated with electronic commerce, the applications for PKI are much broader and include secure Nero Vision Express 2.1.2.12 crack serial keygen mail, payments and electronic checks, Electronic Data Interchange (EDI), secure transfer of Domain Name System (DNS) and routing information, electronic forms, and digitally signed documents. A single "global PKI" is still many years away, that is the ultimate goal of today's work as international electronic commerce changes the way in which we do business in a similar way in which the Internet has changed the way in which we communicate.

    5. CRYPTOGRAPHIC ALGORITHMS IN ACTION

    The paragraphs above have provided an overview of the different types of cryptographic algorithms, as well as some examples of some available protocols and schemes. Table 3 provides a list of some other noteworthy schemes and cryptosystems employed — or proposed — for a variety of functions, most notably electronic commerce and secure communication. The paragraphs below will show several real cryptographic applications that many of us employ (knowingly or not) everyday for password protection and private communication. Some of the schemes described below never were widely deployed but are still historically interesting, thus remain included here. This list is, by no means, 21 Flying Images 2.0 crack serial keygen, exhaustive but describes items that are of significant current and/or historic importance (a subjective judgement, to be sure).

    BitmessageA decentralized, encrypted, peer-to-peer, trustless communications protocol for message exchange. The decentralized design, outlined in "Bitmessage: A Peer-to-Peer Message Authentication and Delivery System" (Warren, 2012), is conceptually based on the Bitcoin model.
    CapstoneA now-defunct U.S. National Institute of Standards and Technology (NIST) 21 Flying Images 2.0 crack serial keygen National Security Agency (NSA) project under the Bush Sr. and Clinton administrations for publicly available strong cryptography with keys escrowed by the government (NIST and the Treasury Dept.). Capstone included one or more tamper-proof computer chips for implementation (Clipper), a secret key encryption algorithm (Skipjack), digital signature algorithm (DSA), key exchange algorithm (KEA), and hash algorithm (SHA).
    Challenge-Handshake Authentication Protocol (CHAP)An authentication scheme that allows one party to prove who they are to a second party by demonstrating knowledge of a shared secret without actually divulging that shared secret to a third party who might be listening. Described in RFC 1994.
    Chips-Message Robust Authentication (CHIMERA)A scheme proposed for authenticating 21 Flying Images 2.0 crack serial keygen data and the spreading code of civilian signals in the Global Positioning System (GPS). This is an KeyGenSumo.com | Y Catalog mechanism to protect the unencrypted civilian signals; GPS military signals are encrypted.
    ClipperThe computer chip that would implement the Skipjack encryption scheme. The Clipper chip was to have had a deliberate backdoor so that material encrypted with this device would not be beyond the government's reach. Described in 1993, Clipper was dead by 1996. See also EPIC's The Clipper Chip Web page.
    Cryptography Research and Evaluation Committees (CRYPTEC)Similar in concept to the NIST AES process and NESSIE, CRYPTEC is the Japanese government's process to evaluate algorithms submitted for government and industry applications. CRYPTEX maintains a list of public key and secret key ciphers, hash functions, MACs, and other crypto algorithms approved for various applications in government environments.
    Derived Unique Key Per Transaction (DUKPT)A key management scheme used for debit and credit card verification with point-of-sale (POS) transaction systems, automated teller machines (ATMs), and other financial applications. In DUKPT, a unique key is derived for each transaction based upon a fixed, shared key in such a way that knowledge of one derived key does not easily yield knowledge of other keys (including the fixed key). Therefore, if one of the derived keys is compromised, neither past nor subsequent transactions are endangered. DUKPT is specified in American National Standard (ANS) ANSI X9.24-1:2009 (Retail Financial Services Symmetric Key Management Part 1: Using Symmetric Techniques) and can be purchased at the ANSI X9.24 Web page.
    ECRYPT Stream Cipher Project (eSTREAM)The eSTREAM project came about as a result of the failure of the NESSIE project to produce a stream cipher that survived cryptanalysis. eSTREAM ran from 2004 to 2008 with the primary purpose of promoting the design of efficient and compact stream ciphers. As of September 2008, the eSTREAM suite contains seven sciphers.
    Escrowed Encryption Standard (EES)Largely unused, a controversial crypto scheme employing the SKIPJACK secret key crypto algorithm and a Law Enforcement Access Field (LEAF) creation method. LEAF was one part of the key escrow system and allowed for decryption of ciphertext messages that had been intercepted by law enforcement agencies. Described more in FIPS PUB 185 (archived; no longer in force).
    Federal Information Processing Standards (FIPS)These computer security- and crypto-related FIPS PUBs are produced by the U.S. National Institute of Standards and Technology (NIST) as standards for the U.S. Government. Current Federal Information Processing Standards (FIPS) related to crytography include:
    FortezzaA PCMCIA card developed by NSA that implements the 21 Flying Images 2.0 crack serial keygen algorithms, intended for use with the Defense Messaging Service (DMS), 21 Flying Images 2.0 crack serial keygen. Originally called Tessera.
    GOSTGOST is a family of algorithms defined in the Russian cryptographic standards, 21 Flying Images 2.0 crack serial keygen. Although most of the specifications are written in Russian, a series of RFCs describe some of the aspects so that the algorithms can be used effectively in Internet applications:
    • RFC 4357: Additional Cryptographic Algorithms for Use with GOST 28147-89, GOST R 34.10-94, GOST R 34.10-2001, and GOST R 34.11-94 Algorithms
    • RFC 4490: Using the GOST 28147-89, GOST R 34.11-94, GOST R 34.10-94, and GOST R 34.10-2001 Algorithms with Cryptographic Message Syntax (CMS)
    • RFC 4491: Using the GOST 21 Flying Images 2.0 crack serial keygen 34.10-94, GOST R 34.10-2001, and GOST R 34.11-94 Algorithms with the Internet X.509 Public Key Infrastructure Certificate and CRL Profile
    • RFC 5830: GOST 28147-89: Encryption, Decryption, and Message Authentication Code (MAC) Algorithms
    • RFC 6986: GOST R 34.11-2012: Hash Function Algorithm
    • RFC 7091: GOST R 34.10-2012: Digital Signature Algorithm (Updates RFC 5832: GOST R 34.10-2001)
    • RFC 7801: GOST R 34.12-2015: Block Cipher "Kuznyechik"
    • RFC 7836: Guidelines on the Cryptographic Algorithms to Accompany the Usage of Standards GOST R 34.10-2012 and GOST R 34.11-2012
    • RFC 8891: GOST R 34.12-2015: Block Cipher "Magma"
    IP Security (IPsec)The IPsec protocol suite is used to provide privacy and authentication services at the IP layer. An overview of the 21 Flying Images 2.0 crack serial keygen suite and of the documents comprising IPsec can be found in RFC 2411. Other documents include:
    • RFC 4301: IP security architecture.
    • RFC 4302: IP Authentication Header (AH), one of the two primary IPsec functions; AH provides connectionless integrity and data origin authentication for IP datagrams and protects against replay attacks.
    • RFC 4303: IP Encapsulating Security Payload (ESP), the other primary IPsec function; ESP provides a variety of security services within IPsec.
    • RFC 4304: Extended Sequence Number (ESN) Addendum, allows for negotiation of a 32- or 64- bit sequence number, used to detect replay attacks.
    • RFC 4305: Cryptographic algorithm implementation requirements for ESP and AH.
    • RFC 5996: The Internet Key Exchange (IKE) protocol, version 2, providing for mutual authentication and establishing and maintaining security associations.
      • IKE v1 was described in three separate documents, RFC 2407 (application of ISAKMP to IPsec), RFC 2408 (ISAKMP, a framework for key management and security associations), and RFC 2409 (IKE, using part of Oakley and part of SKEME in conjunction with ISAKMP to obtain authenticated keying material for use with ISAKMP, and for other security associations such as AH and ESP). IKE v1 is obsoleted with the introduction of IKEv2.
    • RFC 4307: Cryptographic algorithms used with IKEv2.
    • RFC 4308: Crypto suites for IPsec, IKE, and IKEv2.
    • RFC 4309: The use of AES in CBC-MAC mode with IPsec ESP.
    • RFC 4312: The use of the Camellia cipher algorithm in IPsec.
    • RFC 4359: The Use of RSA/SHA-1 Signatures within Encapsulating Security Payload (ESP) and Authentication Header (AH).
    • RFC 4434: Describes AES-XCBC-PRF-128, a pseudo-random function derived from the AES for use with IKE.
    • RFC 2403: Describes use of the HMAC with MD5 algorithm for data origin authentication and integrity protection in both AH and ESP.
    • RFC 2405: Describes use of DES-CBC (DES in Cipher Block Chaining Mode) for confidentiality in ESP.
    • RFC 2410: Defines use of the NULL encryption algorithm (i.e., provides authentication and integrity without confidentiality) in ESP.
    • RFC 2412: Describes OAKLEY, a key determination and distribution protocol.
    • RFC 2451: Describes use of Cipher Block Chaining (CBC) mode cipher algorithms with ESP.
    • RFCs 2522 and 2523: Description of Photuris, a session-key management protocol for IPsec.

    In addition, RFC 6379 describes Suite B Cryptographic Suites for IPsec and RFC 6380 describes the Suite B profile for IPsec.

    IPsec was first proposed for use with IP version 6 (IPv6), but can also be employed with the current IP version, IPv4.

    (See more detail about IPsec below in Section 5.6.)

    Internet Security Association and Key Management Protocol (ISAKMP/OAKLEY)ISAKMP/OAKLEY provide an infrastructure for Internet secure communications. ISAKMP, 21 Flying Images 2.0 crack serial keygen, designed by the National Security Agency (NSA) and described in RFC 2408, is a framework for key management and security associations, independent of the key generation and cryptographic algorithms actually employed. The OAKLEY Key Determination Protocol, described in RFC 2412, is a key determination and distribution protocol using a variation of Diffie-Hellman.
    KerberosA secret key encryption and authentication system, designed to authenticate requests for network resources within a user domain rather than to authenticate messages. Kerberos also uses a trusted third-party approach; a client communications with the Kerberos server to obtain "credentials" so that it may access services at the application server. Kerberos V4 used DES to generate keys and encrypt messages; Kerberos V5 uses DES and other schemes 21 Flying Images 2.0 crack serial keygen key generation.

    Microsoft added support for Kerberos V5 — with some proprietary extensions — in Windows 2000 Active Directory. There are many Kerberos articles posted at Microsoft's Knowledge Base, notably "Kerberos Explained."
    Keyed-Hash Message Authentication Code (HMAC)A message authentication scheme based upon secret key cryptography and the secret key shared between two parties rather than public key methods. Described in FIPS PUB 198 and RFC 2104. (See Section 5.19 below for details IntelliJ IDEA Ultimate 2019.3.1 mac Archives HMAC operation.)
    Message Digest Cipher (MDC)Invented by Peter Gutman, MDC turns a one-way hash function into a block cipher.
    MIME Object Security Services (MOSS)Designed as a successor to PEM to provide PEM-based security services to MIME messages. Described in RFC 1848. Never widely implemented and now defunct.
    Mujahedeen SecretsA Windows GUI, PGP-like cryptosystem. Developed by supporters of Al-Qaeda, the program employs the five finalist AES algorithms, namely, MARS, RC6, Rijndael, Serpent, and Twofish. Also described in Inspire Magazine, Issue 1, pp. 41-44 and Inspire Magazine, Issue 2, pp. 58-59. Additional related information can also be found in "How Al-Qaeda Uses Encryption Post-Snowden (Part 2)."
    New European Schemes for Signatures, Integrity and Encryption (NESSIE)NESSIE was an independent project meant to augment the work of NIST during the AES adoption process by putting out an open call for new cryptographic primitives. The NESSIE project ran from about 2000-2003. While several new block ciper, PKC, MAC, and digital signature algorithms were found during the NESSIE process, no new stream cipher survived cryptanalysis. As a result, 21 Flying Images 2.0 crack serial keygen, the ECRYPT Stream Cipher Project (eSTREAM) was created.
    NSA Suite B CryptographyAn NSA standard for securing information at the SECRET level. Defines use of:
    • Advanced Encryption Standard (AES) with key sizes of 128 and 256 bits, per FIPS PUB 197 for encryption
    • The Ephemeral Unified Model and the One-Pass Diffie Hellman (referred to as ECDH) using the curves with 256 and 384-bit prime moduli, per NIST Special Publication 800-56A for key exchange
    • Elliptic Curve Digital Gone Viral Early Access PC full crack - Free Download - Repack - Hiu Games Algorithm (ECDSA) using the curves with 256 and 384-bit prime moduli, per FIPS PUB 186-3 for digital signatures
    • Secure Hash Algorithm (SHA) using 256 and 384 bits, per FIPS PUB 180-3 for hashing

    RFC 6239 describes Suite B Cryptographic Suites for Secure Shell (SSH) and RFC 6379 describes Suite B Cryptographic Suites for Secure IP (IPsec).

    RFC 8423 reclassifies the RFCs related to the Suite B cryptographic algorithms as Historic, and it discusses the reasons for doing so.

    Pretty Good Privacy (PGP)A family of cryptographic routines for e-mail, file, and disk encryption developed by Philip Zimmermann. PGP 2.6.x uses RSA for key management and digital signatures, IDEA for message encryption, and MD5 for computing the message's hash value; more information can also be found in RFC 1991. IObit Driver Booster Pro 7.4.0.721 Crack Archives 5.x (formerly known as "PGP 3") uses Diffie-Hellman/DSS for key management and digital signatures; IDEA, CAST, or 3DES for message encryption; and MD5 or SHA for 21 Flying Images 2.0 crack serial keygen the message's hash value. OpenPGP, described in RFC 2440, is an open definition of security software based on PGP 5.x. The GNU Privacy Guard (GPG) is a free software version of OpenPGP.

    (See more detail about PGP below in Section 5.5.)

    Privacy Enhanced Mail (PEM)An IETF standard for secure electronic mail over the Internet, including provisions for encryption (DES), authentication, and key management (DES, RSA). Developed by the IETF but never widely used. Described in the following RFCs:
    • RFC 1421: Part I, Message Encryption and Authentication Procedures
    • RFC 1422: Part II, Certificate-Based Key Management
    • RFC 1423: Part III, Algorithms, Modes, and Identifiers
    • RFC 1424: Part IV, Key Certification and Related Services
    Private Communication Technology (PCT)Developed by Microsoft for secure communication on the Internet. PCT supported Diffie-Hellman, 21 Flying Images 2.0 crack serial keygen, Fortezza, and RSA for key establishment; DES, RC2, RC4, and triple-DES for encryption; Driver Booster Crack Archives DSA and RSA message signatures. Never widely used; superceded by SSL and TLS.
    Secure Electronic Transaction (SET)A communications protocol for securing credit card transactions, developed by MasterCard and VISA, in cooperation with IBM, Microsoft, RSA, and other companies. Merged two other protocols: Secure Electronic Payment Protocol (SEPP), an open specification for secure bank card transactions over the Internet developed by CyberCash, GTE, IBM, MasterCard, and Netscape; and Secure Transaction Technology (STT), a secure payment protocol developed by Microsoft and Visa International. Supports DES and RC4 for encryption, and RSA for signatures, key exchange, and public key encryption of bank card numbers, 21 Flying Images 2.0 crack serial keygen. SET V1.0 is described in Book 1, Book 2, and Book 3. SET has been superceded by SSL and TLS.
    Secure Hypertext Transfer Protocol (S-HTTP)An extension to HTTP to provide secure exchange of documents over the World Wide Web. Supported algorithms include RSA and Kerberos for key exchange, DES, IDEA, RC2, and Triple-DES for encryption. Described in RFC 2660. S-HTTP was never as widely used as HTTP over SSL (https).
    Secure Multipurpose Internet Mail Extensions (S/MIME)An IETF secure e-mail scheme superceding PEM, and adding digital signature and encryption capability to Internet MIME messages. S/MIME Version 3.1 is described in RFCs 3850 and 3851, and employs the Cryptographic Message Syntax described in RFCs 3369 and 3370.

    (More detail about S/MIME can be found below in Section 5.15.)
    Secure Sockets Layer (SSL)Developed in 1995 by Netscape Communications to provide application-independent security and privacy over the Internet. SSL is designed so that protocols such as HTTP, FTP (File Transfer Protocol), and Telnet can operate over it transparently. SSL allows both server authentication (mandatory) and client authentication (optional). RSA is used during negotiation to exchange keys and identify the actual cryptographic algorithm (DES, IDEA, RC2, RC4, or 3DES) to use for the session. SSL also uses MD5 for message digests 21 Flying Images 2.0 crack serial keygen X.509 public key certificates. SSL was found to be breakable soon after the IETF announced formation of group to work on TLS and RFC 6176 specifically prohibits the use of SSL v2.0 by TLS clients. SSL version 3.0 is described in RFC 6101. All versions of SSL are now deprecated in favor of TLS; TLS v1.0 is sometimes referred to as "SSL v3.1."

    (More detail about SSL can be found below in Section 5.7.)
    Server Gated Cryptography (SGC)Microsoft extension to SSL that provided strong encryption for online banking and other financial applications using RC2 (128-bit key), RC4 (128-bit key), Sound Keys (for Adobe After Effects) 1.1.1 crack serial keygen (56-bit key), or 3DES (equivalent of 168-bit key). Use of SGC required an Windows NT Server running Internet Information Server (IIS) 4.0 with a valid SGC certificate. SGC was available in 32-bit Windows versions of Internet Explorer (IE) 4.0; support for Mac, Unix, and 16-bit Windows versions of IE was planned, but never materialized, and SGC was made moot when browsers started to ship with 128-bit encryption.
    ShangMi (SM) Cipher SuitesA suite of authentication, encryption, and hash algorithms from the People's Republic of China.
    • SM2 Cryptography Algorithm: A public key crypto scheme based on elliptic curves. An overview of the specification, in Chinese, can be found in GM/T 0009-2012. Additional specifications can be found in:
    • SM3 Cryptographic Hash Algorithm: A hash algorithm operating on 512-bit blocks to produce a 256-bit hash value. Described in GB/T 32905-2016.
    • SM4 Block Cipher Algorithm: 21 Flying Images 2.0 crack serial keygen Feistel block cipher algorithm with a block length and key length of 128 bits, and 32 rounds. Described in GB/T 32907-2016.
    An application of the ShangMi Cipher Suites in TLS can be found in RFC 8998.
    Signal ProtocolA protocol for providing end-to-end encryption for voice calls, video calls, Equilibrio Distante Renato Russo ~ Monte Download instant messaging (including group chats). Employing a combination of AES, ECC, and HMAC algorithms, it offers such features as confidentiality, integrity, authentication, forward/future secrecy, and message repudiation. Signal is particularly interesting because of its lineage and widespread use. The Signal Protocol's earliest versions were known as TextSecure, first developed by Open Whisper Systems in 2013. TextSecure itself was based on a 2004 protocol called Code Vein repack Archives (OTR) Messaging, designed as an improvement over OpenPGP and S/MIME. TextSecure v2 (2014) introduced a scheme called the Axolotl Ratchet for key exchange and added additional communication features. After subsequent iterations improving key management (and the renaming of the key exchange protocol to Double Ratchet), additional cryptographic primitives, and the addition of an encrypted voice calling application (RedPhone), TextSecure was renamed Signal Protocol in 2016. The Ratchet key exchange algorithm is at the heart of the power of this system. Most messaging apps employ the users' public and private keys; the weakness here is that if the phone falls into someone else's hands, all of the messages on the device — including deleted messages — can be decrypted. The Ratchet algorithm generates a set of so-called "temporary keys" for each user, based upon that user's public/private key pair. When two users exchange messages, the Signal protocol creates a secret key by combining the temporary and permanent pairs of public and private keys for both users. Each message is assigned its own secret key. Because the generation of the secret key requires access to both users' private keys, it exists only on their two devices. The Signal Protocol is/has been employed in:
    • WhatsApp (introduced 2014)
    • G Data Software's Secure Chat (introduced 2015; service discontinued 2018)
    • Google's Allo app (introduced 2016; discontinued in favor of Messages app, 2019)
    • Facebook Messenger (introduced 2016)
    • Skype's Private Conversations mode (introduced 2018)
    • All of Google's Rich Communication Services (RCS) on Android systems (introduced 2020)
    A reasonably good writeup of the protocol can be found in "Demystifying the Signal Protocol for End-to-End Encryption (E2EE)" by Kozhukhovskaya, Mora, and Wong (2017).
    Simple Authentication and Security Layer (SASL)A framework for providing authentication and data security services in connection-oriented protocols (a la TCP), described in RFC 4422. It provides a structured interface and allows new protocols to reuse existing authentication mechanisms and allows old protocols to make use of new mechanisms.

    It has been common practice on the Internet to permit anonymous access to various services, employing a plain-text password using a user name of "anonymous" and a password of an email address or some other identifying information. New IETF protocols disallow plain-text logins. The Anonymous SASL Mechanism (RFC 4505) provides a method for anonymous logins within the SASL framework.
    Simple Key-Management for Internet Protocol (SKIP)Key management scheme for secure IP communication, specifically for IPsec, and designed by Aziz and Diffie. SKIP essentially defines a public key infrastructure for the Internet and even uses X.509 certificates. Most public key cryptosystems assign keys on a per-session basis, which is inconvenient for the Internet since IP is connectionless. Instead, SKIP provides a basis for secure communication between any pair of Internet hosts. SKIP can employ DES, 3DES, IDEA, RC2, RC5, MD5, and SHA-1. As it happened, SKIP was not adopted for IPsec; IKE was selected instead.
    SM9Chinese Standard GM/T0044-2016 SM9 (2016) is the Chinese national standard for Identity Based Cryptography. SM9 comprises three cryptographic algorithms, namely the Identity Based Digital Signature Algorithm, Identity Based Key Agreement Algorithm, and Identity Based Key Encapsulation Algorithm (allowing one party to securely send a symmetric key to another party). The SM9 scheme is also described in The SM9 Cryptographic Schemes (Z. Cheng).
    TelegramTelegram, 21 Flying Images 2.0 crack serial keygen, launched in 2013, is a cloud-based instant messaging and voice over IP (VoIP) service, with client app software available for all major computer and mobile device operating systems. Telegram allows users to exchange messages, 21 Flying Images 2.0 crack serial keygen, photos, videos, etc., and supplies end-to-end encryption using a protocol called MTProto. stickers, audio and files of any type. MTProto employs 256-bit AES, 2048-bit RSA, and Diffie-Hellman key exchange. There have been several contriversies with Telegram, not the least of which has to do with the nationality of the founders and the true location of the business, as well as some operation issues. From a cryptological viewpoint, however, one cautionary tale can be found in "On the CCA (in)security of MTProto" (Jakobsen & Orlandi, 2015), who describe some of the crypto weaknesses of the protocol; specifically, that "MTProto does not satisfy the definitions of authenticated encryption (AE) or indistinguishability under chosen-ciphertext attack (IND-CCA)" (p. 1).
    Transmission Control Protocol (TCP) encryption (tcpcrypt)As of 2019, the majority of Internet TCP traffic is not encrypted. The two primary reasons for this are (1) many legacy protocols have no mechanism with which to employ encryption (e.g., without a command such as STARTSSL, the protocol cannot invoke use of any encryption) and (2) many legacy applications cannot be upgraded, so no new encryption can be added. The response from the IETF's TCP Increased Security Working Group was to define a transparent way within the transport layer (i.e., TCP) with which to invoke encryption. The TCP Encryption Negotiation Option (TCP-ENO) addresses these two problems with an out-of-band, fully backward-compatible TCP option with which to negotiate use of encryption. TCP-ENO is described in RFC 8547 and tcpcrypt, 21 Flying Images 2.0 crack serial keygen, an encryption protocol to protect TCP streams, is described in RFC 8548.
    Transport Layer Security (TLS)TLS v1.0 is an IETF specification (RFC 2246) intended to replace SSL v3.0. TLS v1.0 employs Triple-DES (secret key cryptography), SHA (hash), Diffie-Hellman (key exchange), and DSS (digital signatures). TLS v1.0 was vulnerable to attack and updated by v1.1 (RFC 4346), which is now classified as an HISTORIC specification. TLS v1.1 was replaced by TLS v1.2 (RFC 5246) and, subsequently, by v1.3 (RFC 8446).

    TLS is designed to operate over TCP. The IETF developed the Datagram Transport Layer Security (DTLS) protocol to operate over UDP. DTLS v1.2 is described in RFC 6347.

    (See more detail about TLS below in Section 5.7.)
    TrueCryptOpen source, multi-platform cryptography software that can be used to encrypt a file, partition, or entire disk. One of TrueCrypt's more interesting features is that of plausible deniability with hidden volumes or hidden operating systems. The original Web site, truecrypt.org, suddenly went dark in May 2014. The current fork of TrueCrypt is VeraCrypt.

    (See more detail about TrueCrypt below in Section 5.11.)
    X.509ITU-T recommendation for the format of certificates for the public key infrastructure. Certificates map (bind) a user identity to a public key. The IETF application of X.509 certificates is documented in RFC 5280. An Internet X.509 Public Key Infrastructure is further defined in RFC 4210 (Certificate Management Protocols) and RFC 3647 (Certificate Policy and Certification Practices Framework).

    5.1. Password Protection

    Nearly all modern multiuser computer and network operating systems employ passwords at the very least to protect and authenticate users accessing computer and/or network resources. But passwords are not typically kept on a host or server in plaintext, but are generally encrypted using some sort of hash scheme.

    A) /etc/passwd file root:Jbw6BwE4XoUHo:0:0:root:/root:/bin/bash carol:FM5ikbQt1K052:502:100:Carol Monaghan:/home/carol:/bin/bash alex:LqAi7Mdyg/HcQ:503:100:Alex Insley:/home/alex:/bin/bash gary:FkJXupRyFqY4s:501:100:Gary Kessler:/home/gary:/bin/bash todd:edGqQUAaGv7g6:506:101:Todd Pritsky:/home/todd:/bin/bash josh:FiH0ONcjPut1g:505:101:Joshua Kessler:/home/webroot:/bin/bash B.1) /etc/passwd file (with shadow passwords) root:x:0:0:root:/root:/bin/bash carol:x:502:100:Carol Monaghan:/home/carol:/bin/bash alex:x:503:100:Alex Insley:/home/alex:/bin/bash gary:x:501:100:Gary Kessler:/home/gary:/bin/bash todd:x:506:101:Todd Pritsky:/home/todd:/bin/bash josh:x:505:101:Joshua Kessler:/home/webroot:/bin/bash B.2) /etc/shadow file root:AGFw$1$P4u/uhLK$l2.HP35rlu65WlfCzq:11449:0:99999:7::: carol:kjHaN%35a8xMM8a/0kMl1?fwtLAM.K&kw.:11449:0:99999:7::: alex:1$1KKmfTy0a7#3.LL9a8H71lkwn/.hH22a:11449:0:99999:7::: gary:9ajlknknKJHjhnu7298ypnAIJKL$Jh.hnk:11449:0:99999:7::: todd:798POJ90uab6.k$klPqMt%alMlprWqu6$.:11492:0:99999:7::: josh:Awmqpsui*787pjnsnJJK%aappaMpQo07.8:11492:0:99999:7:::

    FIGURE 8: Sample entries in Unix/Linux password files.

    Unix/Linux, for example, uses a well-known hash via its crypt() function. Passwords are stored in the /etc/passwd file (Figure 8A); each record in the file contains the username, hashed password, user's individual and group numbers, user's name, home directory, and shell program; these fields are separated by colons (:). Note that each password is stored as a 13-byte string. The first two characters are actually a salt, randomness added to each password so that if two users have the same password, they will still be encrypted differently; the salt, in fact, provides a means so that a single password might have 4096 different encryptions. The remaining 11 bytes are the password hash, calculated using DES.

    As it happens, the /etc/passwd file is world-readable on Unix systems. This fact, coupled with the weak encryption of the passwords, resulted in the development of the shadow password system where passwords are kept in a separate, non-world-readable file used in conjunction with the normal password file. When shadow passwords are used, the password entry in /etc/passwd is replaced with a "*" or "x" (Figure 8B.1) and the MD5 hash of the passwords are stored in /etc/shadow along with some other account information (Figure 8B.2).

    Windows NT uses a similar scheme to store passwords in the Security Access Manager (SAM) file. In the NT case, all passwords are hashed using the MD4 algorithm, resulting in a 128-bit (16-byte) 21 Flying Images 2.0 crack serial keygen value (they are then obscured using an undocumented mathematical transformation that was a secret until distributed on the Internet). The password password, for example, 21 Flying Images 2.0 crack serial keygen, might be stored as the hash value (in hexadecimal) 60771b22d73c34bd4a290a79c8b09f18.

    Passwords are not saved in plaintext on computer systems precisely so they cannot be easily compromised. For similar reasons, we don't want passwords sent in plaintext across a network. But for remote logon applications, how does a client system identify itself or a user to the server? One mechanism, of course, is to send the password as a hash value and that, 21 Flying Images 2.0 crack serial keygen, indeed, may be done. A weakness of that approach, however, is that an intruder can grab the password off of the network and use an off-line attack (such as a dictionary attack 21 Flying Images 2.0 crack serial keygen an attacker takes every known word and encrypts it with the network's encryption algorithm, hoping eventually to find a match with a purloined password hash), 21 Flying Images 2.0 crack serial keygen. In some situations, an attacker only has to copy the hashed password value and use it later on to gain unauthorized entry without ever learning the actual password.

    An even stronger authentication method uses the password to modify a shared secret between the client and server, but never allows the password in any form to go across the network. This is the basis for the Challenge 21 Flying Images 2.0 crack serial keygen Authentication Protocol (CHAP), the remote logon process used by Windows NT.

    As suggested above, Windows NT passwords are stored in a security file on a server as a 16-byte hash value. In truth, Windows NT stores two hashes; a weak hash based upon the old LAN Manager (LanMan) scheme and the newer NT hash, 21 Flying Images 2.0 crack serial keygen. When a user logs on to a server from a remote workstation, the user is identified by the username, sent across the network in plaintext (no worries here; it's not a secret anyway!). The server then generates a 64-bit random number and sends it to the client (also in plaintext). This number is the challenge.

    Using the LanMan scheme, the client system then encrypts the challenge using DES. Recall that DES employs a 56-bit key, acts on a 64-bit block of data, and produces a 64-bit output. In this case, the 64-bit data block is the random number. The client actually uses three different DES keys to encrypt the random number, producing three different 64-bit outputs. The first key is the first seven bytes (56 bits) of the password's hash value, the second key is the next seven bytes in the password's hash, and the third key is the remaining two bytes of the password's hash concatenated with five zero-filled bytes. (So, for the example above, the three DES keys would 21 Flying Images 2.0 crack serial keygen 60771b22d73c34, 21 Flying Images 2.0 crack serial keygen, bd4a290a79c8b0, and 9f180000000000.) Each key 21 Flying Images 2.0 crack serial keygen applied to the random number resulting in three 64-bit outputs, which comprise the response. Thus, the server's 8-byte challenge yields a 24-byte response from the client and this is all that would be seen on the network. The server, for its part, does the same calculation to ensure that the values match.

    There is, however, a significant weakness to this system. Specifically, the response is generated in such a way as to effectively reduce 16-byte hash to three smaller hashes, of length seven, seven, and two, respectively. Thus, a password cracker has to break at most a 7-byte hash. One Windows NT vulnerability test program that I used in the past reported passwords that were "too short," defined as "less than 8 characters." When I asked how the program knew that passwords were too short, the software's salespeople suggested to me that the program broke the passwords to determine their length. This was, in fact, not the case at all; all the software really had to do was to look at the last eight bytes of the Windows NT LanMan hash to see that the password was seven or fewer characters.

    Consider the following example, showing the LanMan hash of two different short passwords (take a close look at the last 8 bytes):

    AA: 89D42A44E77140AAAAD3B435B51404EE
    AAA: 1C3A2B6D939A1021AAD3B435B51404EE

    Note that the NT hash F1 2019 Download skidrow Archives no such clue:

    AA: C5663434F963BE79C8FD99F535E7AAD8
    AAA: 6B6E0FB2ED246885B98586C73B5BFB77

    It is worth noting that the discussion above describes 21 Flying Images 2.0 crack serial keygen Microsoft version of CHAP, or MS-CHAP (MS-CHAPv2 is described in RFC 2759). MS-CHAP assumes that it is working with hashed values of the password as the key to encrypting the challenge. More traditional CHAP (RFC 1994) assumes that it is starting with passwords in plaintext. The relevance of this observation is that a CHAP client, for example, cannot be authenticated by an MS-CHAP server; both client and server must use Native Instruments - Analog Dreams (KONTAKT) | Download Torrent same CHAP version.

    5.2. Diffie-Hellman Key Exchange

    Diffie and Hellman introduced the concept of public key cryptography. The mathematical "trick" of Diffie-Hellman key exchange is that it is relatively easy to compute exponents compared to computing discrete logarithms. Diffie-Hellman allows two parties — the ubiquitous Alice and Bob — to generate a secret key; they need to exchange some information over an unsecure communications channel to perform the calculation but an eavesdropper cannot determine the shared secret key based upon this information.

    Diffie-Hellman works like this. Alice and Bob start by agreeing on a large prime number, N. They also have to choose some number G so that G<N.

    There is actually another constraint on G, namely that it must be primitive with respect to N. Primitive is a definition that is a little beyond the scope of our discussion but basically G is primitive to N if the set of N-1 values of Gi mod N for i = (1,N-1) are all different. As an example, 2 is not primitive 21 Flying Images 2.0 crack serial keygen 7 because the set of powers of 2 from 1 to 6, mod 7 (i.e., 21 mod 7, 22 mod 7. ., 21 Flying Images 2.0 crack serial keygen, 26 mod 7) = {2,4,1,2,4,1}. On the other hand, 3 is primitive to 7 because the set of powers of 3 from 1 to 6, mod 7 = {3,2,6,4,5,1}.

    (The definition of primitive introduced a new term to some readers, namely mod. The phrase x mod y (and read as written!) means "take the remainder after dividing x by y." Thus, 1 mod 7 = 1, 9 mod 6 = 3, and 8 mod 8 = 0. Read more about the modulo function in the appendix.)

    Anyway, either Alice or Bob selects N and G; they then tell the other party what the values are. Alice and Bob then work independently (Figure 9):

    Alice.

    1. Choose a large random number, XA < N. This is Alice's private key.
    2. Compute YA = GXA mod N. This is Alice's public key.
    3. Exchange public key with Bob.
    4. Compute KA = YBXA mod N
    Bob.

    1. Choose a large random number, XB < N. This is Bob's private key.
    2. Compute YB = GXB mod N. This is Bob's public key.
    3. Exchange public key with Alice.
    4. Compute KB = YAXB mod N
    FIGURE 9: Diffie-Hellman key exchange model.

    Note that XA and XB are kept secret while YA and YB are openly shared; these are the private and public keys, respectively. Based on their own private key and the public key learned from the other party, Alice and Bob have computed their secret keys, KA and KB, respectively, which are equal to GXAXB mod N.

    Perhaps a small example will help here. Although Alice and Bob will really choose large values for N and G, I will use small values for example only; let's use N=7 and G=3, as shown in Figure 10.

    Alice.

    1. Choose private key; XA = 2
    2. Compute public key; YA = 32 mod 7 = 2
    3. Exchange public key with Bob
    4. KA = YBXA mod N = 62 mod 7 = 1
    Bob.

    1. Choose private key; XB = 3
    2. Compute public key; YB = 33 mod 7 = 6
    3. Exchange public key with Alice
    4. KB = YAXB mod N = 23 mod 7 = 1
    FIGURE 10: Diffie-Hellman key exchange example.

    In this example, then, Alice and Bob will both find the secret key 1 which is, indeed, 36 mod 7 (i.e., GXAXB = 32x3). If an eavesdropper (Eve) was listening in on the information exchange between Alice and Bob, she would learn G, N, YA, and YB which is a lot of information but insufficient to compromise the key; as long 21 Flying Images 2.0 crack serial keygen XA and XB remain unknown, K is safe. As stated above, calculating Y = GX is a lot easier than finding X = logG Y.


    A short digression on modulo arithmetic. In the paragraph above, we noted that 36 mod 7 = 1. This can be confirmed, of course, by noting that:

    36 = 729 = 104*7 + 1

    There is a nice property of modulo arithmetic, however, that makes this determination a little easier, namely: (a mod x)(b mod x) = (ab mod x). Therefore, one possible shortcut is to note that 36 = (33)(33). Therefore, 36 mod 7 = (33 mod 7)(33 mod 7) = (27 mod 7)(27 mod 7) = 6*6 mod 7 = 36 mod 7 = 1.


    Diffie-Hellman can also be used to allow key sharing amongst multiple users. Note again that the Diffie-Hellman algorithm is used to generate secret keys, not to encrypt and decrypt messages.

    5.3. RSA Public Key Cryptography

    Unlike Diffie-Hellman, RSA can be used for key exchange as well as digital signatures and the encryption of small blocks of data, 21 Flying Images 2.0 crack serial keygen. Today, RSA is primarily used to encrypt the session key used for secret key encryption (message integrity) or the message's hash value (digital signature). RSA's mathematical hardness comes from the ease in calculating large numbers and the difficulty in finding the prime factors of those large numbers. Although employed with numbers using hundreds of digits, the math behind RSA is relatively straight-forward.

    To create an RSA public/private key pair, here are the basic steps:

    1. Choose two prime numbers, p and q. From these numbers you can calculate the modulus, n = pq.
    2. Select a third number, e, that RPG Maker VX Ace Full Version Download relatively prime to (i.e., it does not divide evenly into) the product (p-1)(q-1). The number e is the public exponent.
    3. Calculate an integer d from the quotient (ed-1)/[(p-1)(q-1)]. The number d is the private exponent.

    The public key is the number pair (n,e). Although these values are publicly known, it is computationally infeasible to determine d from n and e if p and q are large enough.

    To encrypt a message, M, with the public key, create the ciphertext, C, using the equation:

    The receiver then decrypts the ciphertext with the private key using the equation:

    Now, this might look a bit complex and, indeed, the mathematics does take a lot of computer power given the large size of the numbers; since p and q may be 100 digits (decimal) or more, d and e will be about the same size and n may be over 200 digits. Nevertheless, a simple example may help. In this example, the values for p, q, e, and d are purposely chosen to be very small and the reader will see exactly how badly these values perform, but hopefully the algorithm will be adequately demonstrated:

    1. Select p=3 and q=5.
    2. The modulus n = pq = 15.
    3. The value e must be relatively prime to (p-1)(q-1) = (2)(4) = 8. Select e=11.
    4. The value d must be chosen so that (ed-1)/[(p-1)(q-1)] is an integer, 21 Flying Images 2.0 crack serial keygen. Thus, the value (11d-1)/[(2)(4)] = (11d-1)/8 must be an integer. Calculate one possible value, d=3.
    5. Let's suppose that we want to send a message — maybe a secret key — that has the numeric value of 7 (i.e., M=7). [More on this choice below.]
    6. The sender encrypts the message (M) using the public key value (e,n)=(11,15) and computes the ciphertext (C) with the formula C = 711 mod 15 = 1977326743 mod 15 = 13.
    7. The receiver decrypts the 21 Flying Images 2.0 crack serial keygen using the private key value (d,n)=(3,15) and computes the plaintext with the formula M = 133 mod 15 = 2197 mod 15 = 7.

    I choose this trivial example because the value of n is so small (in particular, the value M cannot exceed 21 Flying Images 2.0 crack serial keygen. But here is a more realistic example using larger d, e, and n values, as well as a more meaningful message; thanks to Barry Steyn for permission to use values from his How RSA Works With Examples page.

    Let's say that we have chosen p and q so that we have the following value for n:

    14590676800758332323018693934907063529240187237535716439958187
    10198734387990053589383695714026701498021218180862924674228281
    57022922076746906543401224889672472407926969987100581290103199
    31785875366371086235765651050788371429711563734278891146353510
    2712032765166518411726859837988672111837205085526346618740053

    Let's also suppose that we have selected the public key, e, and private key, d, as follows:

    65537

    89489425009274444368228545921773093919669586065884257445497854
    45648767483962981839093494197326287961679797060891728367987549
    93315741611138540888132754881105882471930775825272784379065040
    15680623423550067240042466665654232383502922215493623289472138
    866445818789127946123407807725702626644091036502372545139713

    Now suppose that our message (M) is the character string "attack at dawn" which has the numeric value (after converting the ASCII characters to a bit string and interpreting that bit string as a decimal number) of 1976620216402300889624482718775150.

    The encryption phase uses the formula C = Me mod n, so C has the value:

    35052111338673026690212423937053328511880760811579981620642802
    34668581062310985023594304908097338624111378404079470419397821
    53784997654130836464387847409523069325349451950801838615742252
    26218879827232453912820596886440377536082465681750074417459151
    485407445862511023472235560823053497791518928820272257787786

    The decryption phase uses the formula M = Cd mod n, so M has the value that matches our original plaintext:

    1976620216402300889624482718775150

    This more realistic example gives just a clue as to how large the numbers are that are used in the real world implementations. RSA keylengths of 512 and 768 bits are considered to be pretty weak. The minimum suggested RSA key is 1024 bits; 2048 and 3072 bits are even better.

    As an aside, Tag Archives: ableton live crack mac Back (http://www.cypherspace.org/~adam/) wrote a two-line Perl script to implement RSA. It employs dc, an arbitrary precision arithmetic package that ships with most UNIX systems:

    print pack"C*",split/\D+/,`echo 21 Flying Images 2.0 crack serial keygen )]}\EsMsKsN0[lN*1lK[d2%Sa2/d0<X+d*lMLa^*lN%0]dsXx++lMlN/dsM0<J]dsJxp"

    Messerschmitt Me 262

    World's first operational jet-powered fighter aircraft

    The Messerschmitt Me 262, nicknamed Schwalbe (German: "Swallow") in fighter versions, or Sturmvogel (German: "Storm Bird") in fighter-bomber versions, was the world's first operational jet-powered fighter aircraft. Design work started before World War II began, but problems with engines, metallurgy and top-level interference kept the aircraft from operational status with the Luftwaffe Mx Player Pro Mod Apk v 1.39.12 (Cracked Version) Full Mod Unlocked mid-1944. The Me 262 was faster and more heavily armed than any Allied fighter, including the British jet-powered Gloster Meteor. One of the most advanced aviation designs in operational use during World War II, the Me 262's roles included light bomber, reconnaissance and experimentalnight fighter versions.

    Me 262 pilots claimed a total of 542 Allied aircraft shot down, although higher claims are sometimes made.[Note 1] The Allies countered its effectiveness in the air by attacking the aircraft on the ground and during takeoff and landing. Strategic materials shortages and design compromises on the Junkers Jumo 004 axial-flow turbojet engines led to reliability problems, 21 Flying Images 2.0 crack serial keygen. Attacks by Allied forces on fuel supplies during the deteriorating late-war situation also reduced the effectiveness of the aircraft as a fighting force. Armament production within Germany was focused on more easily manufactured aircraft.[9] In the end, the Me 262 had a negligible impact on the course of the war as a result of its late introduction and the consequently small numbers put in operational service.

    While German use of the aircraft ended with the close of World War II, a small number were operated by the Czechoslovak Air Force until 1951. It also heavily influenced several designs, such as the Sukhoi Su-9 (1946) and Nakajima Kikka. Captured Me 262s were studied and flight-tested by the major powers, and ultimately influenced the designs of post-war aircraft such as the North American F-86 Sabre, MiG-15 and Boeing B-47 Stratojet. Several aircraft survive on static display in museums, and there are several privately built flying reproductions that use modern General Electric J85 engines.

    Design and development[edit]

    Origins[edit]

    Several years before World War II, the Germans foresaw the great potential for aircraft that used the jet engine constructed by Hans Joachim Pabst von Ohain in 1936. After the successful test flights of the world's first jet aircraft—the Heinkel He 178—within a week of the invasion of Poland to start the war, they adopted the jet engine for an advanced fighter aircraft. As a result, the Me 262 was already under development as Projekt 1065 (P.1065) before the start of World War II. The project originated with a request by the Reichsluftfahrtministerium (RLM, Ministry of Aviation) for a jet aircraft capable of one hour's endurance and a speed of at least 850 km/h (530 mph; 460 kn).[11]Woldemar Voigt headed the design team, with Messerschmitt's chief of development, Robert Lusser, overseeing.[11]

    Plans were first drawn up in April 1939, and the original design was very different from the aircraft that eventually entered service, with wing root-mounted engines,[11] rather than podded ones, when submitted in June 1939.[11] The progression of the original design was delayed greatly by technical issues involving the new jet engine. Because the engines were slow to arrive, Messerschmitt moved the engines from the wing roots to underwing pods, allowing them to be changed more readily if needed; this would turn out to be important, both for availability and maintenance.[12] Since the BMW 003 jets proved heavier than anticipated, the wing was swept slightly, by 18.5°, to accommodate a change in the center of gravity.[12] Funding for the jet engine program was also initially lacking as many high-ranking officials thought the war could easily be won with conventional aircraft. Among those were Hermann Göring, head of the Luftwaffe, who cut the engine development program to just 35 engineers in February 1940 (the month before the first wooden mock-up was completed);[11]Willy Messerschmitt, who desired to maintain mass production of the piston-powered, 1935-origin Bf 109 and the projected Me 209; and Major GeneralAdolf Galland, 21 Flying Images 2.0 crack serial keygen, who had initially supported Messerschmitt through the early development years, flying the Me 262 himself on 22 April 1943. By that time, problems with engine development had slowed production of the aircraft considerably. One particularly acute problem arose with the lack of an alloy with a melting point high enough to endure the high temperatures involved, a problem that by the end of the war had not been adequately resolved. The aircraft made its first successful flight entirely on jet power on 18 July 1942, powered by a pair of Jumo 004 engines, after a November 1941 flight (with BMW 003s) ended in a double flameout.[14]

    The project aerodynamicist on the design of the Me 262 was Ludwig Bölkow. He initially designed the wing using NACAairfoils modified with an elliptical nose section.[15] Later in the design process, these were changed to AVL derivatives of NACA airfoils, the NACA 00011-0.825-35 being used at the root and the NACA 00009-1.1-40 at the tip.[16] The elliptical nose derivatives of the NACA airfoils were used on the horizontal and vertical tail surfaces. Wings were of single-spar cantilever construction, Enscape3D Free Download Archives stressed skins, varying from 3 mm (0.12 in) skin thickness at the root to 1 mm (0.039 in) at the tip. To expedite construction, save weight and use less strategic materials, late in the war, wing interiors were not painted. The wings were fastened to the fuselage at four points, using a pair of 20 mm (0.79 in) and forty-two 8 mm (0.31 in) bolts.

    In mid-1943, Adolf Hitler envisioned the Me 262 as a ground-attack/bomber aircraft rather than a defensive interceptor. The configuration of a high-speed, light-payload Schnellbomber ("fast bomber") was intended to penetrate enemy airspace during the expected Allied invasion of France. 21 Flying Images 2.0 crack serial keygen edict resulted in the development of (and concentration on) the Sturmvogel variant. It is debatable to what extent Hitler's interference extended the delay in bringing the Schwalbe into operation;[19] it appears engine vibration issues were at least as costly, if not more so.[14]Albert Speer, then Minister of Armaments and War Production, in his memoirs claimed Hitler originally had blocked mass production of the Me 262, before agreeing in early 1944. Hitler rejected arguments the aircraft would be more effective as a fighter against the Allied bombers destroying large parts of Germany and wanted it as a bomber for revenge attacks. According to Speer, Hitler felt its superior speed compared to other fighters of the era meant it could not be attacked, and so preferred it for high altitude straight flying.[21]

    The Me 262 is often referred to as a "swept wing" design as the production aircraft had a small, but significant leading edge sweep of 18.5° which likely provided an advantage by increasing the critical Mach number.[22] Sweep, uncommon at the time, was added after the initial design of the aircraft. The engines proved heavier than originally expected, and the sweep was added primarily to position the center of lift properly relative to the center of mass. (The original 35° sweep, proposed by Adolf Busemann, was not adopted.)[23] On 1 March 1940, instead of moving the wing backward on its mount, the outer wing was re-positioned slightly aft; the trailing edge of the midsection of the wing remained unswept. Based on data from the AVA Göttingen and wind tunnel results, the inboard section's leading edge (between the nacelle and wing root) was later swept to the same angle as the outer panels, from the "V6" sixth prototype onward throughout volume production.

    Test flights[edit]

    Testing showed that the Me 262 handled much better than previous fighters such as the Bf 109 or Fw 190. Handling was so improved over the previous aircraft that a report by Major Ernst Englander stated that any Bf 109 pilot could convert to the Me 262 with only an hour of instruction. According to his report, even bomber pilots who converted to fly the Me 262 only required three instruction flights, and less than 5% had any difficulty retraining, 21 Flying Images 2.0 crack serial keygen. The Me 262 had a gentle stall and gentle landing characteristics compared to previous German fighters. Its handling improved with speed and would lose much less speed during turning. It had a cruising speed of 465 mph, which was faster than the top speed of most other fighters of the day. It also had far better visibility in every direction compared to previous German fighters. Due to lack of engine torque, if a single engine was lost the aircraft remained easily controlled and landed without issue. Its only major deficiency was that brakes could not be used until the nose wheel had touched down, because engaging them before would smash the nose wheel strongly into the runway, potentially destroying the nose wheel and the aircraft. The quality of the aircraft was high, with only 10% of aircraft returned for minor defects such as wings being out of alignment by under 1 degree. It could reach 515 mph without issue, although because it could reach extreme speeds in dives, components such as bomb racks would sometimes tear off.[26][unreliable source?]

    Test flights began on 18 April 1941, with the Me 262 V1 example, bearing its Stammkennzeichen radio code letters of PC+UA, but since its intended BMW 003turbojets were not ready for fitting, a conventional Junkers Jumo 210 engine was mounted in the V1 prototype's nose, driving a propeller, to test the Me AnvSoft Photo Flash Maker Pro v5.x crack serial keygen V1 airframe.[27] When the BMW 003 engines were installed, the Jumo was retained for safety, which proved wise as both 003s failed during the first flight and the pilot had to land using the nose-mounted engine alone. The V1 through V4 prototype airframes all possessed what would become an uncharacteristic feature for most later jet aircraft designs, a fully retracting conventional gear setup with a retracting tailwheel—indeed, the very first prospective German "jet fighter" airframe design ever flown, the Heinkel He 280, used a retractable tricycle landing gear from its beginnings and flying on jet power alone as early as the end of March 1941.

    Silhouette of the V3 prototype – V1 through V4 similar. Note retracting conventional tail wheel gear

    The V3 third prototype airframe, with the code PC+UC, became a true jet when it flew on 18 July 1942 in Leipheim near Günzburg, Germany, piloted by test pilot Fritz Wendel.[28] This was almost nine months ahead of the British Gloster Meteor's first flight on 5 March 1943. Its retracting conventional tail wheel gear (similar to other contemporary piston-powered propeller aircraft), a feature shared with the first four Me 262 V-series airframes, caused its jet exhaust to deflect off the runway, with the wing's turbulence negating the effects of the elevators, and the first takeoff attempt was cut short.

    On the second attempt, Wendel solved the problem by tapping the aircraft's brakes at takeoff speed, 21 Flying Images 2.0 crack serial keygen, lifting the horizontal tail out of the wing's turbulence. The aforementioned initial four prototypes (V1-V4) were built with the conventional gear configuration. Changing to a tricycle arrangement—a permanently fixed undercarriage on the fifth prototype (V5, code PC+UE), with the definitive fully retractable nosewheel gear on the V6 (with Stammkennzeichen code VI+AA, from a new code block) and subsequent aircraft corrected this problem.[Note 2]

    Test flights continued over the next year, but engine problems continued to plague the project, the Jumo 004 being only marginally more reliable than the lower-thrust (7.83 kN/1,760 lbf) BMW 003. Airframe modifications were complete by 1942 but, hampered by the lack of engines, serial production did not begin until 1944, and deliveries were low, with 28 Me 262s in June, 59 in July, but only 20 in August.[page needed]

    By Summer 1943, the Jumo 004A engine had passed several 100-hour tests, with a time between overhauls of 50 hours being achieved.[32] However, the Jumo 004A engine proved unsuitable for full-scale production because of its considerable weight and its high utilization of strategic material (Ni, Co, Mo), which were in short supply. 21 Flying Images 2.0 crack serial keygen, the 004B engine was designed to use a minimum amount of strategic materials. All high heat-resistant metal parts, including the combustion chamber, were changed to mild steel (SAE 1010) and were protected only against oxidation by aluminum coating. The total engine represented a design compromise to minimize the use of strategic materials and to simplify manufacture.[32] With the lower-quality steels used in the 004B, the engine required overhaul after just 25 hours for a metallurgical test on the turbine. If it passed the test, the engine was refitted for a further 10 hours of usage, but 35 hours marked the absolute limit for the turbine wheel.[33] While BMW's and Junkers' axial compressor turbojet engines were characterised by a sophisticated design that could offer a considerable advantage – also used in a generalized form for the contemporary American Westinghouse J30 turbojet – the lack of rare materials for the Jumo 004 design put it at a disadvantage compared to the "partly axial-flow" Power Jets W.2/700 turbojet engine which, despite its own largely centrifugal compressor-influenced design, provided (between an operating overhaul interval of 60–65 hours[34]) an operational life span of 125 hours. Frank Whittle concludes in his final assessment over the two engines: "it was in the quality of high temperature materials that the difference between German and British engines was most marked"[35]

    Operationally, carrying 2,000 litres (440 imperial gallons; 530 US gallons) of fuel in two 900-litre (200-imperial-gallon; 240-US-gallon) tanks, one each fore and aft of the cockpit; and a 200-litre (44-imperial-gallon; 53-US-gallon) ventral fuselage tank beneath,[Note 3] the Me 262 would have a total flight endurance of 60 to 90 minutes. Fuel was usually J2 (derived from brown coal), with the option of diesel or a mixture of oil and high octane B4 aviation petrol. Fuel consumption was double the rate of typical twin-engine fighter aircraft of the era, which led to the installation of a low-fuel warning indicator in the cockpit that notified pilots when remaining fuel fell below 250 l (55 imp gal; 66 US gal).

    Unit cost for an Me 262 airframe, less engines, armament, and electronics, was 87,400 RM.[Note 4] To build one airframe took around 6,400-man-hours.

    Operational history[edit]

    Me 262 A-1a on display at RAF Cosford. Some A-1a aircraft (including this example), like the A-2a bomber variant, attached additional hardpoints for extra weapons near the ejector chutes of the cannons, 21 Flying Images 2.0 crack serial keygen, such as a bomb rack under each side of the nose.

    Introduction[edit]

    On 19 April 1944, Erprobungskommando 262 was formed at Lechfeld just south of Augsburg, as a test unit (Jäger Erprobungskommando Thierfelder, commanded by HauptmannWerner Thierfelder) to introduce the Me 262 into service and train a corps of pilots to fly it. On 26 July 1944, Leutnant Alfred Schreiber with the 262 A-1a W.Nr. 130 017 damaged a Mosquito reconnaissance aircraft of No. 540 Squadron RAF PR Squadron, which was allegedly lost in a crash upon landing at an air base in Italy. Other sources state the aircraft was damaged during evasive manoeuvres and escaped.

    Major Walter Nowotny was assigned as commander after the death of Thierfelder in July 1944, and the unit redesignated Kommando Nowotny. Essentially a trials and development unit, it mounted the world's first jet fighter operations. Trials continued slowly, with initial operational missions against the Allies in August 1944, and the unit made claims for 19 Allied aircraft in exchange for six Me 262s lost.[43]

    Despite orders to stay grounded, 21 Flying Images 2.0 crack serial keygen, Nowotny chose to fly a mission against an enemy bomber formation flying some 9,100 m (30,000 ft) above, on 8 November 1944. He claimed two P-51Ds destroyed before suffering engine failure at high altitude, 21 Flying Images 2.0 crack serial keygen. Then, while diving and trying to restart his engines, he was attacked by other Mustangs, forced to bail out, and died. The Kommando was then withdrawn for further flight training and a revision of combat tactics to optimise the Me 262's strengths.[citation needed]

    On 26 November 1944, a Me 262A-2a Sturmvogel of III.Gruppe/KG 51 'Edelweiß' based at Rheine-Hopsten Air Base cowin.gov.in - Covid Vaccine Registration for 18 years old link & Process Osnabrück was the first confirmed ground-to-air kill of a jet combat aircraft. The Me 262 was shot down by a Bofors gun of B.11 Detachment of 2875 Squadron RAF Regiment at the RAF forward airfield of Helmond, near Eindhoven. Others were lost to ground fire on 17 21 Flying Images 2.0 crack serial keygen 18 December when the same airfield was attacked at intervals by a total of 18 Me 262s and the guns of 2873 and 2875 Squadrons RAF Regiment damaged several, causing at least two to crash within a few miles of the airfield. In February 1945, a B.6 gun detachment of 2809 Squadron RAF Regiment shot down another Me 262 over the airfield of Volkel. NCH Switch Plus v1.24 crack serial keygen final appearance of 262s over Volkel was in 1945 when yet another fell to 2809's guns.[45]

    By January 1945, Jagdgeschwader 7 (JG 7) had been formed as a pure jet fighter wing, partly based at Parchim[46] although it was several weeks before it was operational. In the meantime, a bomber unit—I Gruppe, Kampfgeschwader 54 (KG(J) 54)—redesignated as such on 1 October 1944[47] through being re-equipped with, and trained to use the Me 262A-2a fighter-bomber for use in a ground-attack role. However, the unit lost 12 jets in action in two weeks for minimal returns.[citation needed]Jagdverband 44 (JV 44) was another Me 262 fighter unit, of squadron (Staffel) size given the low numbers of available personnel, formed in February 1945 by Lieutenant General Adolf Galland, who had recently been dismissed as Inspector of Fighters. Galland was able to draw into the unit many of the most experienced and decorated Luftwaffe fighter pilots from other units grounded by lack of fuel.

    During March, Me 262 fighter units were able, for the first time, to mount large-scale attacks on Allied bomber formations. On 18 March 1945, thirty-seven Me 262s of JG 7 intercepted a force of 1,221 bombers and 632 escorting fighters. They shot down 12 bombers and one fighter for the loss of three Me 262s. Although a 4:1 ratio was exactly what the Luftwaffe would have needed to make an impact on the war, the absolute scale of their success was minor, as it represented only 1% of the attacking force.

    In the last days of the war, Me 262s from JG 7 and other units were committed in ground assault missions, in an attempt to support German troops fighting Red Army forces. Just south of Berlin, halfway between Spremberg and the German capital, Wehrmacht's 9th Army (with elements from the 12 Army and 4th Panzer Army) was assaulting the Red Army's 1st Ukrainian Front. To support this attack, on 24 April, JG 7 dispatched thirty-one Me 262s on a strafing mission in the Cottbus-Bautzen area. Luftwaffe pilots claimed six lorries and seven Soviet aircraft, but three German jets were lost. On the evening of 27 April, thirty-six Me 262s from JG 7, III.KG(J)6 and KJ(J)54 were sent against Soviet forces that were attacking German troops in the forests north-east of Baruth. They succeeded in strafing 65 Soviet lorries, after which the Me 262s intercepted low flying Il-2 Sturmoviks searching for German tanks. The jet pilots claimed six Sturmoviks for the loss of three Messerschmitts. During operations between 28 April and 1 May Soviet fighters and ground fire downed at least ten more Me 262s from JG 7.[49] However, JG 7 managed to keep its jets operational until the end of the war. And on 8 May, at around 4:00 p.m. Oblt. Fritz Stehle of 2./JG 7, while flying a Me 262 on the Erzgebirge, attacked a formation of Soviet aircraft. He claimed a Yakovlev Yak-9, but the plane shot down was probably a P-39 Airacobra. Soviet records show that they lost two Airacobras, one of them probably downed by Stehle, 21 Flying Images 2.0 crack serial keygen, who would thus have scored the 21 Flying Images 2.0 crack serial keygen Luftwaffe air victory of the war.[50]

    Me 262B-1a/U1 night fighter, Wrknr. 110306, with FuG 218 Neptunantennae in the nose and second seat for a radar operator. This airframe was surrendered to the RAF at Schleswig in May 1945 and taken to the UK for testing.

    Several two-seat trainer variants of the Me 262, the Me 262 B-1a, 21 Flying Images 2.0 crack serial keygen, had been adapted through the Umrüst-Bausatz 1 factory refit package as night fighters, complete with on-board FuG 218 Neptun high-VHF band radar, using Hirschgeweih ("stag's antlers") antennae with a set of dipole elements shorter than the Lichtenstein SN-2 had used, as the B-1a/U1 version. Serving with 10. StaffelNachtjagdgeschwader 11, near Berlin, these few aircraft (alongside several single-seat examples) accounted for most of the 13 Mosquitoes lost over Berlin in the first three months of 1945.[51] Intercepts were generally or entirely made using Wilde Sau methods, rather than AI radar-controlled interception. As the two-seat trainer was largely unavailable, many pilots made their first jet flight in a single-seater without an instructor.[52]

    Despite its deficiencies, the Me 262 clearly marked the beginning of the end of piston-engined aircraft as effective fighting machines. Once airborne, it could accelerate to speeds over 850 km/h (530 mph), about 150 km/h (93 mph) faster than any Allied fighter operational in the European Theater of Operations.[53]

    The Me 262's top ace[Note 5] was probably HauptmannFranz Schall with 17 kills, including six four-engine bombers and ten P-51 Mustang fighters, although fighter ace OberleutnantKurt Welter claimed 25 Mosquitos and two four-engine bombers shot down by night and two further Mosquitos by day. Most of Welter's claimed night kills were achieved by eye, even though Welter had tested a prototype Me 262 fitted with FuG 218 Neptun radar. Another candidate for top ace on the aircraft was OberstleutnantHeinrich Bär, who is credited with 16 enemy aircraft[54] while flying Me262s out of his total of 240 aircraft shot down.[55]

    Anti-bomber tactics[edit]

    The other main USAAF bomber was the B-24 Liberator. This aircraft "Do Bunny" was shot down by a Me 262 on 25 March 1945 over Soltau, Germany

    The Me 262 was so fast that German pilots needed new tactics to attack Allied bombers. In the head-on attack, the combined closing speed of about 320 m/s (720 mph) was too high for accurate shooting, 21 Flying Images 2.0 crack serial keygen, with ordnance that could only fire about 44 shells a second (650 rounds/min from each cannon) in total from the quartet of them. Even from astern, 21 Flying Images 2.0 crack serial keygen closing speed was too great to use the short-ranged quartet of MK 108 cannon to maximum effect. Therefore, a roller-coaster attack was devised. The Me 262s approached from astern and about 1,800 m higher (5,900 ft) than the bombers. From about five km behind (3.1 mi), they went into a shallow dive that took them through the escort fighters with little risk of interception. When they were about 1.5 km astern (0.93 mi) and 450 m (1,480 ft) below the bombers, they pulled up sharply to reduce speed. On levelling off, they MovieMator Video Editor Pro Crack 3.3.0 Activation Code 2021 one km astern (1,100 yd) and overtaking the bombers at about 150 km/h (93 mph), well placed to attack them.[56]

    Since the 30mm MK 108 cannon's short barrels and low muzzle velocity (only 540 m/s (1,900 km/h; 1,200 mph)) rendered it inaccurate beyond 600 m (660 yd; 21 Flying Images 2.0 crack serial keygen, coupled with the jet's velocity, which required breaking off at 200 m (220 yd; 660 ft) to avoid colliding with the target, Me 262 pilots normally commenced firing at 500 m (550 yd; 1,600 ft).[57] Gunners of Allied bomber aircraft found their electrically powered gun turrets had problems tracking the jets. Target acquisition was difficult because the jets closed into firing range quickly and remained in firing position only briefly, using their standard attack profile, which proved more effective.[58]

    Mock-up of an Me 262A-1a/R7 with R4M underwing rocket racks on display at the Technikmuseum Speyer, Germany.

    A prominent Royal Navy test pilot, Captain Eric Brown, chief naval test pilot and commanding officer of the Captured Enemy Aircraft Flight Royal Aircraft Establishment, who tested the Me 262 noted:

    This was a Blitzkrieg aircraft. You whack in at your bomber. It was never meant to be a dogfighter, it was meant to be a destroyer of bombers. The great problem with it was it did not have dive brakes. For example, if you want to fight and destroy a B-17, you come in on a dive. The 30mm cannon were not so accurate beyond 600 metres [660 yd; 2,000 ft]. So you normally came in at 600 yards [550 m; 1,800 ft] and would open fire on your B-17. And your closing speed was still high and since you had to break away at 200 metres [220 yd; 660 ft] to avoid a collision, you only had two seconds firing time. Now, in two seconds, you can't sight. You can fire randomly and hope for the best. If you want to sight and fire, you need to double that time to four seconds. And with dive brakes, you could have done that.[57]

    Eventually, German pilots developed new combat tactics to counter Allied bombers' defences. Me 262s, equipped with up to 24 unguided folding-fin R4M rockets—12 in each of two underwing racks, outboard of the engine nacelle—approached from the side of a bomber formation, where their silhouettes were widest, and while still out of range of the bombers' machine guns, fired a salvo of rockets with strongly brisantHexogen-filled warheads, exactly the same explosive in the shells fired by the Me 262A's quartet of MK 108 cannon. One or two of these rockets could down even the famously rugged Boeing B-17 Flying Fortress,[59] from the "metal-shattering" brisant effect of the fast-flying rocket's 520 g (18 oz) explosive warhead. The much more massive BR 21 large-calibre rockets, used from their tubular launchers in undernose locations for an Me 262A's use (one either side of the nosewheel well) were only as fast as the MK 108's shells.

    Though this broadside-attack tactic was effective, it came too late to have a real effect on the war, and only small numbers of Me 262s were equipped with the rocket packs. Most of those so equipped were Me 262A-1a models, members of Jagdgeschwader 7. This method of attacking bombers became the standard, and mass deployment of Ruhrstahl X-4 guided missiles was cancelled. Some nicknamed this tactic the Luftwaffe's Wolf Pack, as the fighters often made runs in groups of two or three, fired their rockets, then returned to base. On 1 September 1944, USAAF GeneralCarl Spaatz expressed the fear that if greater numbers of German jets appeared, they could inflict losses heavy enough to force cancellation of the Allied bombing offensive by daylight.[62]

    Counter-jet tactics[edit]

    This airframe, Wrknr. 111711, was the first Me 262 to come into Allied hands when its German test pilot defected on 31 March 1945. The aircraft was then shipped to the United States for testing.

    The Me 262 was difficult to counter because its high speed and rate of climb made it hard to intercept. However, as with other turbojet engines at the time, the Me 262's engines did not provide sufficient thrust at low airspeeds and throttle response was slow, so that in certain circumstances such as takeoff and landing the aircraft became a vulnerable target. Another disadvantage that pioneering jet aircraft of the World War II era shared, was the high risk of compressor stall and if throttle movements were too rapid, the engine(s) could suffer a flameout, 21 Flying Images 2.0 crack serial keygen. The coarse opening of the throttle would cause fuel surging and lead to excessive jet pipe temperatures. Pilots were instructed to operate the throttle gently and avoid quick changes. German engineers introduced an automatic throttle regulator later in the war but it only partly alleviated the problem.[citation needed]

    The plane had, by contemporary standards, 21 Flying Images 2.0 crack serial keygen, a high wing loading (294.0 kg/m2, 60.2 lbs/ft2) that required higher takeoff and landing speeds. Due to poor throttle response, the engines' tendency for airflow disruption that could cause the compressor to stall was ubiquitous. The high speed of the Me 262 also presented problems when engaging enemy aircraft, the high-speed convergence allowing Me 262 pilots little time to line up their targets or acquire the appropriate amount of deflection. This problem faces any aircraft that approaches another from behind at much higher speed, as the slower aircraft in front can always pull a tighter turn, forcing the faster aircraft to overshoot.[citation needed]

    I passed one that looked as if it was hanging motionless in the air (I am too fast!). The one above me went into a steep right-hand turn, his pale blue underside standing out against the purple sky. Another banked right in front of the Me's nose. Violent jolt as I flew through his airscrew 21 Flying Images 2.0 crack serial keygen. Maybe a wing's length away. That one in the gentle left-hand curve! Swing her round. I was coming from underneath, eye glued to the sight (pull her tighter!). A throbbing in the wings as my cannon pounded briefly. Missed him. Way behind his tail. It was exasperating. I would never be able to shoot one down like this. They were like a sack of fleas. A prick of doubt: is this really such a good fighter? Could one in fact, successfully attack a group of erratically banking fighters with the Me 262?

    — Johannes Steinhoff, Luftwaffe fighter ace[64]

    Luftwaffe pilots eventually learned how to handle the Me 262's higher speed and the Me 262 soon proved a formidable air superiority fighter, with pilots such as Franz Schall managing to shoot 21 Flying Images 2.0 crack serial keygen seventeen enemy fighters in the Me 262, ten of them American P-51 Mustangs. Other notable Me 262 aces included Georg-Peter Eder, with twelve enemy fighters to his credit (including nine P-51s), Erich Rudorffer also with twelve enemy fighters to his credit, Walther Dahl with eleven (including three Lavochkin La-7s and six P-51s) and Heinz-Helmut Baudach with six (including MovieMator Video Editor Pro Crack 3.3.0 Activation Code 2021 Spitfire and two P-51s) amongst many others.[citation needed]

    Pilots soon learned that the Me 262 was quite maneuverable despite its high wing loading and lack of low-speed thrust, especially if attention was drawn to its effective maneuvering speeds. The controls were light and effective right up to the maximum permissible speed and perfectly harmonised, 21 Flying Images 2.0 crack serial keygen. The inclusion of full span automatic leading-edge slats,[Note 6] something of a "tradition" on Messerschmitt fighters dating back to the original Bf 109's outer wing slots of a similar type, helped increase the overall lift produced by the wing by as much as 35% in tight turns or at low speeds, greatly improving the aircraft's turn performance as well as its landing and takeoff characteristics.[67] As many pilots soon found out, the Me 262's clean design also meant that it, like all jets, held its speed in tight turns much better than conventional propeller-driven fighters, which was a great potential advantage in a dogfight as it meant better energy retention in maneuvers.[68][69]

    January 1945 Me-262 being shot down. Note jettisoned canopy and empty cockpit. As seen from USAAFP-51 Mustang gun camera

    Too fast to catch for the escorting Allied fighters, the Me 262s were almost impossible to head off. [Note 7] As a result, Me 262 pilots were relatively safe from the Allied fighters, as long as they did not allow themselves to get drawn into low-speed turning contests and saved their maneuvering for higher speeds, 21 Flying Images 2.0 crack serial keygen. Combating the Allied fighters could be effectively done the same way as the U.S. fighters fought the more nimble, but slower, Japanese fighters in the Pacific.[citation needed]

    Allied pilots soon found that the only reliable way to destroy the jets, as with the even faster Me 163B Komet rocket fighters, was to attack them on the ground or during takeoff or landing. Luftwaffe airfields identified as jet bases were frequently bombed by medium bombers, and Allied fighters patrolled over 21 Flying Images 2.0 crack serial keygen fields to attack jets trying to land. The Luftwaffe countered by installing extensive Flak alleys of anti-aircraft guns along the approach lines to protect the Me 262s from the ground—and by providing top cover during the jets' takeoff and landing with the most advanced Luftwaffe single-engined fighters, the Focke-Wulf Fw 190D and (just becoming available in 1945) Focke-Wulf Ta 152H.[71] Nevertheless, in March–April 1945, Allied fighter patrol patterns over Me 262 airfields resulted in numerous jet losses.[citation needed]

    As the Me 262A's pioneering Junkers Jumo 004axial-flowjet engines needed careful nursing by their pilots, these jet aircraft were particularly vulnerable during takeoff and landing.[72] Lt. Chuck Yeager of the 357th Fighter Group was one of the first American pilots to shoot down an Me 262, which he caught during its landing approach.[73][74] On 7 October 1944, Lt. Urban Drew of the 365th Fighter Group shot down two Me 262s that were taking off, while on the same day Lt. Col. Hubert Zemke, who had transferred to the Mustang equipped 479th Fighter Group, shot down what he thought was a Bf 109, only to have his gun camera film reveal that it may have been an Me 262.[75] On 25 February 1945, Mustangs of the 55th Fighter Group surprised an entire Staffel of Me 262As at takeoff and destroyed six jets.[76]

    The British Hawker Tempest scored several kills against the new German jets, including the Messerschmitt Me 262. Hubert Lange, a Me 262 pilot, said: "the Messerschmitt Me 262's most dangerous opponent was the British Hawker Tempest—extremely fast at low altitudes, highly manoeuvrable and heavily armed."[77] Some were destroyed with a tactic known to the Tempest-equipped No. 135 Wing RAF as the "Rat Scramble":[78] Tempests on immediate alert took off when an Me 262 was reported airborne. They did not intercept the jet, but instead flew towards the Me 262 and Ar 234 base at Hopsten air base.[79][Note 8] The aim was to attack jets on their landing approach, when they were at their most vulnerable, travelling slowly, with flaps down and incapable of rapid acceleration. The German response was the construction of a "flak lane" of over 150 emplacements of the 20 mm Flakvierling quadruple autocannon batteries at Rheine-Hopsten to protect the approaches.[80][Note 9] After seven Tempests were lost to flak at Hopsten in a week, the "Rat Scramble" was discontinued.[81]

    High-speed research[edit]

    Adolf Busemann had proposed swept wings as early as 1935; Messerschmitt researched the topic from 1940. In April 1941, Busemann proposed fitting a 35° swept wing (Pfeilflügel II, literally "arrow wing II") to the Me 262, the same wing-sweep angle later used on both the American F-86 Sabre and Soviet Mikoyan-Gurevich MiG-15 fighter jets. Though this was not implemented, he continued with the projected HG II and HG III (Hochgeschwindigkeit, "high-speed") derivatives in 1944, designed with a 35° and 45° wing sweep, respectively.

    Interest in high-speed flight, which led him to initiate work on swept wings starting in 1940, is evident from the advanced developments Messerschmitt had on his 21 Flying Images 2.0 crack serial keygen board in 1944. While the Me 262 V9 Hochgeschwindigkeit I (HG I) flight-tested in 1944 had only small changes compared to combat aircraft, most notably a low-profile canopy—tried as the Rennkabine (literally "racing cabin") on the ninth Me 262 prototype for a short time—to reduce drag, the HG II and HG III designs were far more radical. The projected HG II combined the low-drag canopy with a 35° wing sweep and a V-tail (butterfly tail). The HG III had a conventional tail, but a 45° wing sweep and turbines embedded in the wing roots.

    Messerschmitt also conducted a series of flight tests with the series production Me 262. Dive tests determined that the Me 262 went out of control in a dive at Mach 0.86, and that higher Mach numbers would cause a nose-down trim that the pilot could not counter. The resulting steepening of the dive would lead to even higher speeds and the airframe would disintegrate from excessive negative g loads.[citation needed]

    Messerschmitt believed the HG series of Me 262 derivatives was capable of reaching transonic Mach numbers in level flight, with the top speed of the HG III being projected as Mach 0.96 at 6,000 m (20,000 ft) altitude.[85] After the war, the Royal Aircraft Establishment, at that time one of the leading institutions in high-speed research, re-tested the Me 262 to help with British attempts at exceeding Mach 1. The RAE achieved speeds of up to Mach 0.84 and confirmed the results from the Messerschmitt dive-tests. The Soviets ran similar tests.

    After Willy Messerschmitt's death in 1978, the former Me 262 pilot Hans Guido Mutke claimed to have exceeded Mach 1 on 9 April 1945 in a Me 262 in a "straight-down" 90° dive. This claim relies solely on Mutke's memory of the incident, which recalls effects other Me 262 pilots observed below the speed of sound at high indicated airspeed, but with no altitude reading required to determine the speed. The pitot tube used to measure airspeed in aircraft can give falsely elevated readings as the pressure builds up inside the tube at high speeds. The Me 262 wing had only a slight sweep, incorporated for trim (center of gravity) reasons and likely would have suffered structural ravity vst Archives due to divergence at high transonic speeds. One airframe—the aforementioned Me 262 V9, Werknummer 130 004, with Stammkennzeichen of VI+AD, was prepared as the HG I test airframe with the low-profile Rennkabine racing-canopy and may have 21 Flying Images 2.0 crack serial keygen an unofficial record speed for a turbojet-powered aircraft of 975 km/h (606 mph), altitude unspecified,[87] even with the recorded wartime airspeed record being set on 6 July 1944, by another Messerschmitt design—the Me 163B V18 rocket fighter setting a 1,130 km/h (700 mph) record, but landing with a nearly disintegrated rudder surface.[88][89]

    Production[edit]

    Underground manufacture of Me 262s

    About 1,400 planes were produced, but a maximum of 200 were operational at any one time. According to sources they destroyed from 300 to 450 enemy planes, with the Allies destroying about one hundred Me 262s in the air.[71] While Germany was bombed intensively, 21 Flying Images 2.0 crack serial keygen, production of the Me 262 was dispersed into low-profile production facilities, sometimes little more than clearings in the forests of Germany and occupied countries. From the end of February to the end of March 1945, approximately sixty Me 262s were destroyed in attacks on Obertraubling and thirty at Leipheim;[90] the Neuburg jet plant itself was bombed on 19 March 1945.[91]

    Large, heavily protected underground factories were constructed – as with the partly-buried 21 Flying Images 2.0 crack serial keygen I complex for Jumo 004 jet engine production – to take up production of the Me 262, safe from bomb attacks. 21 Flying Images 2.0 crack serial keygen disused mine complex under the Walpersberg mountain was adapted for the production of complete aircraft. These were hauled to the flat top of the hill where a runway had been cleared and flown out. Between 20 and 30 Me 262s were built here, the underground factory being overrun by Allied troops before it could reach a meaningful output. Wings were produced in Germany's oldest motorway tunnel at Engelberg, to the west of Stuttgart. At B8 Bergkristall-Esche II, a vast network of tunnels was excavated beneath St. Georgen/Gusen, Austria, where slave labourers of concentration camp Gusen II produced fully equipped fuselages for the Me 262 at a monthly rate of 450 units on large assembly lines from early 1945.[92] Gusen II was known as one of the harshest concentration camps; the typical life expectancy was six months.[93] An estimated 35,000 to 50,000 people died on the forced labour details for the Me 262.[94]

    Postwar history[edit]

    After the end of the war, the Me 262 and other advanced German technologies were quickly swept up by the Soviets, British and Americans, as part of the USAAF's Operation Lusty. Many Me 262s were found in readily repairable condition and were confiscated. The Soviets, British and Americans wished to evaluate the technology, particularly the engines.

    During testing, the Me 262 was found to be faster than the British Gloster Meteor jet fighter, and had better visibility to the sides and rear (mostly due to the canopy frames and the discoloration caused by the plastics used in the Meteor's construction), and was a superior gun platform to the Meteor F.1 which had a tendency to snake at high speed and exhibited "weak" aileron response.[95] The Me 262 had a shorter range than the Meteor and had less reliable engines.

    The USAAF compared the P-80 Shooting Star and Me 262, concluding that the Me 262 was superior in acceleration and speed, with similar climb performance. The Me 262 appeared to have a higher critical Mach number than any American fighter.[96]

    The Americans also tested a Me 262A-1a/U3 unarmed photo reconnaissance version, which was fitted with a fighter nose and a smooth finish. Between May and August 1946, the aircraft completed eight flights, lasting four hours and forty minutes. Testing was discontinued after four engine changes were required during the course of the tests, 21 Flying Images 2.0 crack serial keygen, culminating in two single-engine landings.[97] These aircraft were extensively studied, aiding development of early US, British and Soviet jet fighters. The F-86, designed by engineerEdgar Schmued, used a slat design based on the Me 262's.[98]

    Avia S-92, Kbely Museum, Prague, 2012.

    The Czechoslovak aircraft industry continued to produce single-seat (Avia S-92) and two-seat (Avia CS-92) variants of the Me 262 after World War II. From August 1946, a total of nine S-92s and three two-seater CS-92s were completed and test flown. They were introduced in 1947 and in 1950 were supplied to the 5th Fighter Squadron, 21 Flying Images 2.0 crack serial keygen, becoming the first jet fighters to serve in the Czechoslovak Air Force. These were kept flying until 1951,[4] when they were replaced in service by Soviet jet fighters. Both versions are on display at the PragueAviation museum in Kbely.

    Flyable reproductions[edit]

    Me 262 (A-1c) replica of (A1-a), Berlin air show, 2006.

    In January 2003, the American Me 262 Project, based in Everett, Washington, completed flight testing to allow the delivery of partially updated spec reproductions of several versions of the Me 262 including at least two B-1c two-seater variants, one A-1c single-seater and two "convertibles" that could be switched between the A-1c and B-1c configurations. All are powered by General Electric CJ610 engines and feature additional safety features, such as upgraded brakes and strengthened landing gear. The "c" suffix refers to the new CJ610 powerplant and has been informally assigned with the approval of the Messerschmitt Foundation in Germany[99] (the Werknummer of the reproductions picked up where the last wartime produced Me 262 left off – a continuous airframe serial number run with a near 60-year production break), 21 Flying Images 2.0 crack serial keygen.

    Flight testing of the first newly manufactured Me 262 A-1c (single-seat) variant (Werknummer 501244) was completed in August 2005. The first of these machines (Werknummer 501241) went to a private owner in Photolemur Crack Archives southwestern United States, while the second (Werknummer 501244) was delivered to the Messerschmitt Foundation at Manching, Germany. This aircraft conducted a private test flight in late April 2006 and made its public debut in May at the ILA 2006. The new Me 262 flew during the public flight demonstrations.[100] Me 262 Werknummer 21 Flying Images 2.0 crack serial keygen was delivered to the Collings Foundation as White 1 of JG 7; this aircraft offered ride-along flights starting in 2008.[101] The third replica, a non-flyable Me 262 A-1c, was delivered to the Evergreen Aviation & Space Museum in May 2010.[102]

    Variants[edit]

    Note:- U = Umrüst-Bausatz – conversion kit installed at factory level, denoted as a suffix in the form /Un.[103]

    Me 262 A-0
    Pre-production aircraft fitted with two Jumo 004B turbojet engines, 23 built.
    Me 262 A-1a "Schwalbe"
    Primary production version, usable as both fighter (interceptor) and fighter-bomber.[27]
    Me 262 A-1a/U1
    Single prototype with a total of six nose mounted guns, two 20 mm (0.787 in) MG 151/20 cannon, two 30 mm (1.181 in) MK 103 cannon, and two 30 mm (1.181 in) MK 108 cannon.[27]
    Me 262 A-1a/U2
    Single prototype with FuG 220 Lichtenstein SN-2 90 MHz radar transceiver and Hirschgeweih (stag's antlers) antenna array, for trials as a night-fighter.[27]
    Me 262 A-1a/U3
    Reconnaissance version modified in small numbers, 21 Flying Images 2.0 crack serial keygen, with Rb 20/30[104] cameras mounted in the 21 Flying Images 2.0 crack serial keygen or alternatively one Rb 20/20[104] and one Rb 75/30[104] (Rb – Reihenbildner – series-picture, topographic camera). Some retained one 30 mm (1.181 in) MK 108 cannon, but most were unarmed.
    Me 262 A-1a/U4
    Bomber destroyer version, two prototypes with an adapted 50 mm (1.969 in) MK 214 (intended armament) or BK 5 (test ordnance only) anti-tank gun in the nose.[27]
    Me 262 A-1a/U5
    Heavy jet fighter with six 30 mm (1.181 in) MK 108 cannon in the nose.[27]
    Me 262 A-1b
    Trio of A-1a evaluation versions, starting with Werknummer 170 078, re-engined with two BMW 003A turbojets in place of the Jumo 004s, maximum speed 800 km/h (500 mph; 430 kn).[105]
    Me 262 A-2a "Sturmvogel"
    Definitive bomber version retaining only the two lower 30 mm (1.181 in) MK 108 cannon.[27]
    Me 262 A-2a/U1
    Single prototype with advanced bombsight.
    Me 262 A-2a/U2
    Two prototypes with glazed nose for accommodating a bombardier.[27]
    Me 21 Flying Images 2.0 crack serial keygen A-3a
    Proposed ground-attack version.
    Me 262 A-4a
    Reconnaissance version.
    Me 262 A-5a
    Definitive reconnaissance version used in setup 2020 Archives numbers at end of the war.[27]
    Me 262 B-1a
    Two-seat trainer.[27]
    Me 262 B-1a/U1
    Me 262 B-1a trainers converted into provisional night fighters, FuG 218 Neptun radar, with Hirschgeweih (eng:antler) eight-dipole antenna array.[citation needed]
    Me 262 B-2
    Proposed night fighter version with stretched fuselage.
    Me 262C
    Proposed development prototypes in four differing designs, meant to augment or replace the Jumo 004 jets with 21 Flying Images 2.0 crack serial keygen rocket propulsion, as the "Home Protector" (Heimatschützer) series.
    Me 262 C-1a
    Single prototype [made from Me 262A Werknummer 130 186] of rocket-boosted interceptor (Heimatschützer I) with Walter HWK 109-509 liquid-fuelled rocket in the tail, first flown with combined jet/rocket power on 27 February 1945.[106]
    Me 262 C-2b
    Single prototype [made from Me 262A Werknummer 170 074] of rocket-boosted interceptor (Heimatschützer II) with two BMW 003R "combined" powerplants (BMW 003 turbojet, with a single 9.8 kN (2,200 lbf) thrust BMW 109-718 liquid-fuelled rocket engine mounted atop the rear of each jet exhaust) for boosted thrust, only flown once with combined jet/rocket power on 26 March 1945.[107]
    Me 262 C-3
    Heimatschützer III – proposed version with Jumo 004 turbojet 21 Flying Images 2.0 crack serial keygen replaced with Walter HWK RII-211 Liquid-fuelled rocket engines.[108]
    Me 262 C-3a
    Heimatschützer IV - a rocket-boosted interceptor with a Walter HWK 109-509S-2 rocket motor housed in a permanent belly pack. Prototypes and initial production aircraft were captured before completion.[109]
    Me 262 D-1
    Proposed variant to carry Jagdfaust mortars.
    Me 262 E-1
    Proposed variant based on A-1a/U4 with a 50 mm (1.969 in) MK 114 cannon.[110]
    Me 262 E-2
    Proposed rocket-armed variant carrying up to 48 × R4M rockets.
    Me 262 HG-I
    "High Speed" variant, modified A-1a with new "racing" style cockpit and additional pieces were added to wing roots at the front.[111][112][113]
    Me 262 HG-II
    Second "High Speed" variant, more heavily modified A-1a with "racing" style cockpit and wings swept at 35-degree angle and engine nacelles were moved closer to fuselage. A new butterfly V-shaped tail was tested but was too unstable in wind tunnel tests, so normal tail 21 Flying Images 2.0 crack serial keygen kept.[111][112][113]
    Me 262 HG-III
    Proposed Third "High Speed" variant, only progressed to wind tunnel model stage. This was the last and the pinnacle of the Me-262 aerodynamical possibility, which would have been built from the ground up as a new Me-262 instead of modifying older ones. In the Me-262 HG-III, its wings were swept at 45 degrees, it also had the aforementioned "racing" style cockpit, however, the largest change was the moving of the engine nacelles right into the fuselage side and changing the engines to the more powerful Heinkel HeS 011 engines.[111][112][113]
    Me 262 S
    Zero-series model for Me 262 A-1a
    Me 262 W-1
    Provisional designation for Me 262 with 2x 2.7 kN (610 lbf) Argus As 014pulse jet engines
    Me 262 W-3
    Provisional designation for Me 262 with 2x 4.90 kN (1,102 lbf) "square-intake" Argus As 044pulse jet engines
    Me 262 Lorin
    Provisional designation for Me 262 with 2x Lorinramjet booster engines in "over-wing" mounts, one above each of the Jumo turbojet nacelles.

    Rüstsätze (field modification kits)[edit]

    Rüstsatze may be applied to various sub-types of their respective aircraft type, denoted as a suffix in the form /Rn. Data from: Messerschmitt Me 262A Schwalbe[103][114]

    /R1: Underfuselage pylon for 500 l (110.0 imp gal; 132.1 US gal) external fuel tank.
    /R2: Ratog installation for two Rheinmetall 109-502 solid rocket engines.
    /R3: BMW 003R rocket boosted turbojet installation.
    /R4: Installation of the FuG 350 Zc Naxos radar warning receiver / detector.
    /R5: The standard 4x 30 mm (1.181 in) MK 108 cannon installation.
    /R6: Jabo (JagdBomber) equipment, such as bombsights and bomb racks.
    /R7: Underwing installation of 12x R4M rockets carried on wooden racks.
    /R8: R110BS Air to air rocket installation.
    /R9: Ruhrstahl Ru 344 X-4 air-to-air missile installation.

    Postwar variants[edit]

    Avia S-92[115]
    Czech-built Me 262 A-1a (fighter)[116]
    Avia CS-92
    Czech-built Me 262 B-1a (fighter trainer, two seats)

    Reproductions[edit]

    A series of reproductions was constructed by American company Legend Flyers (later Me 262 Project) of Everett, Washington.[117] The Jumo 004 engines of the original are replaced by more reliable General Electric CJ610 engines. The first Me 262 reproduction (a two-seater) took off for the first time in December 2002 and the second one in August 2005. This one was delivered to the Messerschmitt Foundation and was presented at the ILA airshow in 2006.[118]

    A-1c: American privately built, based on A-1a configuration.
    B-1c: American privately built, based on B-1a configuration.
    A/B-1c: American privately built, convertible between A-1c and B-1c configuration.

    Operators[edit]

    Surviving aircraft[edit]

    Me 262A-2a (Black X), Australia, 2012
    Me 262B-1a/U1 (Red 8), South Africa, 2008
    Me 262 B-1a (White 35), at Willow Grove, Pa., in 2007; relocated to and on display in Pensacola, Fl.
    Me 262 A-1a/R7, W.Nr.500071 White 3, III./JG 7
    Deutsches Museum,[119] Munich, Germany. This aircraft, flown by Hans Guido Mutke while a pilot of 9. Staffel/JG 7, was confiscated by Swiss authorities on 25 April 1945 after Mutke made an emergency landing in Switzerland due to lack of fuel (80 litres were remaining, 35 litres were usually burnt in one minute). Removed (2015?) from main museum for restoration and relocated to: Deutsches Museum Flugwerft Schleissheim, Ferdinand-Schulz-Allee (for navigation systems), 85764 Oberschleissheim, Germany.[120]
    Me 262 A-1a
    Reconstructed from parts of crashed and incomplete Me 262s. Luftwaffenmuseum der Bundeswehr, Germany.
    Me 262 A-1a W.Nr.501232 Yellow 5, 3./KG(J)6
    National Museum of the United States Air Force, Wright-Patterson Air Force Base, Dayton, Ohio, US.
    Me 262 A-1a/U3 W.Nr.500453
    Flying Heritage Collection, Everett, Washington, US, currently in US undergoing restoration to flying condition. It is intended to fly using its original Jumo 004 engines.[121] 21 Flying Images 2.0 crack serial keygen aircraft was bought from The Planes of Fame, Chino, California.
    Me 262 A-1a/R7 W.Nr.500491 Yellow 7, II./JG 7
    National Air and Space Museum, Smithsonian Institution, Washington, DC, US. Possesses twin original underwing racks for 24 R4M unguided rockets.
    Me 262 A-1a W.Nr.112372
    RAF MuseumCosford, Cosford, United Kingdom.
    Me 262 A-2a W.Nr.500200 Black X 9K+XK, 2 Staffel./KG 51
    Australian War Memorial, Canberra, Australia. Built at Regensburg in March 1945, same batch from which the Deutsches Museum White 3 was built. Flown by Fahnenjunker Oberfeldwebel Fröhlich and surrendered at Fassberg. It remains the only Me 262 left in existence wearing original (albeit worn, as seen in the picture) colours. Its markings show both the Unit signatures along with the Air Ministry colours applied at Farnborough, where Jogos Torrents - Baixar Games via Torrent Grátis Completo para PC em PT-BR was allocated reference Air Min 81. Restoration was completed in 1985 and the aircraft was put up on display. The Australian War Memorial's website states that the aircraft "is the only Me 262 bomber variant to survive, and is the only remaining Me 262 wearing its original paint".[123]
    Me 262 B-1a/U1, W.Nr.110305 Red 8
    South African National Museum of Military History, Johannesburg, South Africa.
    Me 262 B-1a, W.Nr.110639 White 35
    National Museum of Naval Aviation, Pensacola, Florida (previously at NAS/JRB Willow Grove, Willow Grove, Pennsylvania, 21 Flying Images 2.0 crack serial keygen, US)
    Avia S-92
    Prague Aviation Museum, Kbely, Prague, 21 Flying Images 2.0 crack serial keygen, Czech Republic.
    Avia CS-92
    Prague Aviation Museum, Kbely, 21 Flying Images 2.0 crack serial keygen, Prague, Czech Republic.

    Specifications (Messerschmitt Me 262 A-1a)[edit]

    3-view drawing of REBORN Survival Download Free Full PC Game For Mac Torrent Messerschmitt Me 262.

    Data from Quest for Performance[22] Original Messerschmitt documents

    General characteristics

    • Crew: 1
    • Length: 10.6 m (34 ft 9 in)
    • Wingspan: 12.6 m (41 ft 4 in)
    • Height: 3.5 m (11 ft 6 in)
    • Wing area: 21.7 m2 (234 sq ft)
    • Aspect ratio: 7.32
    • Empty weight: 3,795 kg (8,367 lb) [125]
    • Gross weight: 6,473 kg (14,271 lb) [125]
    • Max takeoff weight: 7,130 kg (15,719 lb) [125]
    • Powerplant: 2 × Junkers Jumo 004B-1 axial-flow turbojet engines, 8.8 kN (1,980 lbf) thrust each

    Performance

    • Maximum speed: 900 km/h (560 mph, 490 kn)
    • Range: 1,050 km (650 mi, 570 nmi)
    • Service ceiling: 11,450 m (37,570 ft)
    • Rate of climb: 20 m/s (3,900 ft/min) at max weight of 7,130 kg (15,720 lb)
    • Thrust/weight: 0.28

    Armament

    • Guns: 4 × 30 mm MK 108 cannon (the A-2a had only two cannons)
    • Rockets: 24 × 55 mm (2.2 in) R4M rockets
    • Bombs: 2 × 250 kg (550 lb) bombs or 2 × 500 kg (1,100 lb) bombs (A-2a variant)

    Notable appearances in media[edit]

    Main article: Messerschmitt Me 262 in fiction

    See also[edit]

    Aircraft of comparable role, configuration, and era

    Related lists

    References[edit]

    Notes[edit]

    1. ^Morgan and Weal estimate that jet fighters of all types produced 745 victories.
    2. ^The nosewheel was a 66 cm × 16 cm (26.0 in × 6.3 in) item identical to the Bf 109F's main gear wheel, fitted with a Buna rubber tire and pneumatic drum brake.
    3. ^According to Stapfer, the smaller fuel tank had a capacity of up to 237.75 21 Flying Images 2.0 crack serial keygen gallons (197.97 imperial gallons; 900.0 litres).
    4. ^By comparison, a new Volkswagen Type 1 was priced at RM990.[38]
    5. ^For a list of Luftwaffe jet aces, see List of German World War II jet aces
    6. ^The leading edge slats, manufactured by Arwa Strumpfwerke of Auerbach, were divided into three unconnected sections on each wing and each was fastened to the wing by two hinges. The slats lowered the stalling speed of the aircraft to roughly 21 Flying Images 2.0 crack serial keygen to 170 km/h (86 to 92 kn; 99 to 106 mph) depending on load out. They deployed automatically below 300 km/h (160 kn; 190 mph) on takeoff or landing and at 450 km/h (240 kn; 280 mph) in turn or climb.
    7. ^According to aviation historian Mike Spick, it could take eight Mustangs to neutralize a single Me 262, by continually cutting across the circle inside it. Against multiple jet attackers, an effective defense was 21 Flying Images 2.0 crack serial keygen impossible.[70]
    8. ^Other aircraft based there included Bf 109 and Fw 190-day fighters and Bf 110 and He 219 night fighters. The base was closer to the town of Hopsten than the city of Rheine and is no longer active.
    9. ^As well as the flak guns, several piston engine fighter units based in the area were tasked to cover the jets as they landed.

    Citations[edit]

    1. ^ abBalous 21 Flying Images 2.0 crack serial keygen al. 1995, p. 53.
    2. ^Kitchen, Martin (2015). Speer: Hitler's Architect. Yale University Press. pp. 213 & 243. ISBN .
    3. ^ abcdeChristopher, John. The Race for Hitler's X-Planes (The Mill, 21 Flying Images 2.0 crack serial keygen History Press, 2013), p. 59.
    4. ^ abChristopher, p. 60.
    5. ^ abChristopher, p. 61.
    6. ^Bölkow, L. "Mit dem Pfeilflügel zum Hochgeschwindigkeitsflug." 50 Jahre Turbostrahlflug. Bonn: DGLR-Bericht, 1989, pp. 225–287.
    7. ^Lednicer, David. The Incomplete Guide to Airfoil Usage. Champaign, Illinois: UIUC Applied Aerodynamics Group, 2010. Retrieved: 19 May 2011.
    8. ^"Stormbirds History."Stormbirds.com.. Retrieved 19 May 2011.
    9. ^Speer 1997, p. 363.
    10. ^ abLoftin, L.K. Jr. Quest for Performance: The Evolution of Modern Aircraft.NASA SP-468. Retrieved: 25 September 2018. Chapter 11 Part 2
    11. ^Christopher, John. The Race for Hitler's X-Planes (History Press, The Mill, Gloucestershire, 2013, p. 48.
    12. ^Operational performance and deployment of Me 262. Major Ernst Englander. 1945.
    13. ^ abcdefghijFord, Roger (2013). Germany's Secret Weapons of World War II. London, United Kingdom: Amber Books. p. 224, 21 Flying Images 2.0 crack serial keygen. ISBN .
    14. ^Warsitz 2009, p. 143.
    15. ^ abMeher-Homji; Cyrus B. (1997). "The Development of the Junkers Jumo 004B". Journal of Engineering for Gas Turbines and Power. 119 (4): 785. doi:10.1115/1.2817055.
    16. ^CIOS XXIV-6 "Gas Turbine Development: BMW-Junkers-Daimler-Benz" London, 1946 p. 24
    17. ^The Gloster Meteor, 1962 p. 28
    18. ^Sir Frank Whittle, Jet: the Story of a Pioneer (1953) pp. 92–93
    19. ^Gilmore, Robert. The KdF Wagens: Germany's Car for the Masses, in VW Trends, February 1992, pp. 36–40.
    20. ^Smith 1971, p. 103.
    21. ^Oliver, Kingsley M. The RAF Regiment at War 1942–1946. Great Britain: Pen & Sword. pp. 111–112.
    22. ^Schwerin-Parchim Flughafen – Pläne (German), 21 Flying Images 2.0 crack serial keygen, Schweriner Volkszeitung, 23 June 2015
    23. ^de Zeng, H.L.; Stankey, D.G.; Creek, Eddie J. (2007). Bomber Units of the Luftwaffe 1933–1945; A Reference Source, Volume 1, 21 Flying Images 2.0 crack serial keygen. Ian Allan Publishing. p. 183. ISBN .
    24. ^Bergstrom, Christer (2008). = Bagration to Berlin: The Final Air Battles in the East: 1944–1945. Great Britain: Ian Allan. p. 123. ISBN .
    25. ^Bergstrom, Christer (2008). = 24x7 Scheduler 2.4.0 crack serial keygen to Berlin: The Final Air Battles in the East: 1944–1945. Great Britain: Ian Allan. pp. 123–124. ISBN .
    26. ^"Luftwaffe Resource Center – Fighters/Destroyers – A Warbirds Resource Group Site". www.warbirdsresourcegroup.org. Retrieved 11 October 2019.
    27. ^Hecht, Heinrich (1990). The World's First Turbojet Fighter – Messerschmitt Me 262. Schiffer. ISBN .
    28. ^"Messerschmitt Me 262 A-1a Schwalbe (Swallow)". National Air and Space Museum, 21 Flying Images 2.0 crack serial keygen. 22 April 2016. Retrieved 11 October 2019.
    29. ^Miller, David A. (1997). Die Schwertertraeger Der Wehrmacht: Recipients of the Knight's Cross with Oakleaves and Swords. Merriam Press. ISBN .
    30. ^Isby, David C. (19 October 2016). Luftwaffe Fighter Force: The View from the Cockpit. Frontline. ISBN .
    31. ^Spick 1983, p. 112.
    32. ^ abThompson with Smith 2008, p. 233.
    33. ^Hutchinson, Herbert A. (18 October 2018). Inside History of the Usaf Lightweight Fighters, 1900 to 1975. Xlibris Corporation, 21 Flying Images 2.0 crack serial keygen. ISBN .
    34. ^Brown 2006, 21 Flying Images 2.0 crack serial keygen, p. 101.
    35. ^Press, Merriam (2018). World War 2 In Review No. 33: German Airpower. Lulu.com. ISBN .
    36. ^Spick 1983, pp. 112–113.
    37. ^"Theories of Flight devices."centennialofflight.net, 21 Flying Images 2.0 crack serial keygen, 2003. Retrieved: 11 April 2010.
    38. ^Loftin, Laurence K., Jr. "Quest for Performance: The Evolution of Modern Aircraft, Part II: The Jet Age, Chapter 11: Early Jet Fighters, Pioneer jet 21 Flying Images 2.0 crack serial keygen NASA SP-468, NASA Scientific and Technical Information Branch, 2004 via hq.nasa.gov. Retrieved: 11 April 2010.
    39. ^Summary of debriefing of Me-262 test pilot and flight instructor Hans Fey.
    40. ^Spick 1997, p. 165.
    41. ^ abLevine 1992, 21 Flying Images 2.0 crack serial keygen, pp. 158, 185.
    42. ^Forsyth 1996, pp. 149, 194.
    43. ^Niderost, Eric (21 June 2017). "Chuck Yeager: Fighter Pilot". Warfare History Network. Archived from the original on 29 March 2018. Retrieved 29 March 2018.
    44. ^"Encounter Report". 6 November 1944. Archived from the original on 22 February 2018. Retrieved 29 March 2018.
    45. ^Scutts 1994, p. 58.
    46. ^Illustrated Encyclopedia of Aircraft, p. 12.
    47. ^"Hawker Tempest."hawkertempest.se. Retrieved: 1 January 2012.
    48. ^Clostermann 1953, p. 181.
    49. ^"Die Geschichte des Fliegerhorstes"etnp.de. Retrieved: 7 July 2016.
    50. ^"The "Westfalen-Wing" in Rheine-Hopsten Air Base."Archived 15 October 2013 at the Wayback Machineetnep.de. Retrieved: 1 January 2012.
    51. ^Thomas and Shores 1988, p. 129.
    52. ^Carruthers, Bob (2013). 21 Flying Images 2.0 crack serial keygen. 262 Stormbird ascending. Barnsley. ISBN . OCLC 870833813.
    53. ^Flying Review, 1960s, date unknown
    54. ^ de Bie, Rob. "Me 163B Komet – Me 163 Production – Me 163B: Werknummern list."robdebie.home. Retrieved: 28 July 2013.
    55. ^"Me 163."walterwerke.co.uk. Retrieved: 28 August 2010.
    56. ^Englander, Major Ernst. "Summary of debriefing German pilot Hans Fey on operational performance & late war deployment of the Me 262 jet fighter."USAAC, Spring 1945 via zenoswarbirdvideos.com. Retrieved: 11 April 2010.
    57. ^Blue, Allan G. "491st Mission List – June 1944 TO April 1945."Archived 5 September 2008 at the Wayback Machine491st.org, 21 Flying Images 2.0 crack serial keygen. Retrieved: 11 April 2010.
    58. ^Haunschmied et al. 2008, p. 127.
    59. ^"Gusen". www.ushmm.org. United States Holocaust Memorial Museum.
    60. ^Pfeffer, Anshel. "Dark skies". The Jerusalem Post. Retrieved 6 July 2018.
    61. ^Ethell and Price 1994, pp. 97–99.
    62. ^Ethell and Price 1994, p. 180.
    63. ^Butler 1994, p. [page needed].
    64. ^Blair 1980,[page needed]
    65. ^"Aircraft Profiles: Configuration data."Me 262 Project.. Retrieved 29 January 2012.
    66. ^Jim1410. "Me 262 Flys Again!" – via YouTube.
    67. ^"Messerschmitt Me 262 Flight Program."Archived 11 October 2007 at the Wayback MachineCollingsfoundation.org.. Retrieved: 19 May 2011.
    68. ^Bailey, Stewart. "New Me-262 Reproduction lands at the Museum."Evergreen Aviation & Space Museum, 25 June 2010. Retrieved: 7 June 2011.
    69. ^ abParsch, Andreas, 21 Flying Images 2.0 crack serial keygen. "German Military Aircraft Designations (1933–1945)". www.designation-systems.net. Retrieved 14 July 2014.
    70. ^ abc"Luftwaffe Reconnaissance Camera Systems". www.airrecce.co.uk. Archived from the original on 27 May 2014. Retrieved 14 July 2014.
    71. ^Smith, J. Richard; Creek, Eddie (1982). Jet Planes of the Third Reich. Boylston, MA USA: Monogram Aviation Publications. pp. 143–144, 146–147. ISBN .
    72. ^Reddin, Shamus. "Me.262 Heimatschützer I. The Walter 109-509.S1 Assisted Take-Off Unit."Archived 27 April 21 Flying Images 2.0 crack serial keygen at the Wayback MachineWalter Website (archived), 27 April 2009. Retrieved: 10 August 2013.
    73. ^"Video of BMW 718 rocket engine test firing on this aircraft."German Jet Power, 1 August 2013. Retrieved: 10 August 2013.
    74. ^Baker, David (1997). Messerschmitt Me 262, 21 Flying Images 2.0 crack serial keygen. Marlborough, Wiltshire [England]: Crowood. ISBN .
    75. ^Reddin, Shamus. "Me.262 Heimatschützer IV. The Walter 109-509.S2 Assisted Take-Off Unit."Archived 27 April 2009 at the Wayback MachineWalter Website (archived), 27 April 2009. Retrieved: 10 August 2013.
    76. ^Green, William (28 March 2016). Famous Fighters Of The Second World War, Volume One, 21 Flying Images 2.0 crack serial keygen. Pickle Partners Publishing. ISBN .
    77. ^ abcLuftwaffe Secret Projects Fighters 1939–1945 by Walter Schick, Ingolf Meyer, Elke Weal, John Weal
    78. ^ abcmesserschmitt Geheimprojekte by Willy radinger and Walter Schick
    79. ^ abcLuftwaffe Secret Projects Fighters 1939–1945 by Walter Schick, Ingolf Meyer, 21 Flying Images 2.0 crack serial keygen, Elke Weal, John Weal p. 85
    80. ^Peçzkowski, Robert (2002).
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    On 30 November 2010 the ATSB had, in close consultation with Rolls-Royce and the UK Air Accidents Investigation Branch, established that the occurrence was directly related to the fatigue cracking Wondershare Filmora 9.5 Full Version Key Features an oil feed stub pipe within the No.2 engine’s HP/IP bearing support structure. The ATSB identified the following safety issue:

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    Issue number:AO-2010-089-SI-01
    Who it affects:Aircraft equipped with Rolls-Royce plc Trent 900 series engines
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    Intermediate pressure turbine overspeed and burst following failure of drive arm due to internal AutoCad 2022 Crack + Keygen Torrent Download fire

    Following the separation of the IP turbine disc from the drive arm, the engine behaved in a manner that differed from the engine manufacturer’s modelling and experience with other engines in the Trent family, with the result that the IP turbine disc accelerated to a rotational speed in excess of its design capacity whereupon it burst in a hazardous manner.

    Issue number:AO-2010-089-SI-02
    Who it affects:Ownres and operators of Trent 900 engines
    Status:Adequately addressed

    Release of non-conforming oil feed stub pipes into service

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    Issue number:AO-2010-089-SI-03
    Who it affects:Rolls-Royce plc, owners and operators of Trent 900 engines
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    Consultation between manufacturing engineers and design engineers to ensure maintenance of design intent

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    Issue number:AO-2010-089-SI-04
    Who it affects:Engine manufacturer Rolls-Royce plc
    Status:Adequately addressed

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    Issue number:AO-2010-089-SI-05
    Who it affects:Engine manufacturer Rolls-Royce plc
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    Who it affects:Engine manufacturer Rolls-Royce plc
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    Who it affects:Engine manufacturer Rolls-Royce plc
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    Who it affects:Engine manufacturer Rolls-Royce plc
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    Who it affects:Rolls-Royce plc
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    Who it affects:Engine manufacturer Rolls-Royce plc
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    Who it affects:Airframe certification authorities
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