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Feistel Cipher
In cryptography, a Feistel cipher (also known as Luby–Rackoff block cipher) is a symmetric structure used in the construction of block ciphers, named after the German-born physicist and cryptographer Horst Feistel, who did pioneering research while working for IBM; it is also commonly known as a Feistel network. A large number of block ciphers use the scheme, including the US Data Encryption Standard, the Soviet/Russian GOST and the more recent Blowfish and Twofish ciphers. In a Feistel cipher, encryption and decryption are very similar operations, and both consist of iteratively running a function called a " round function" a fixed number of times. History Many modern symmetric block ciphers are based on Feistel networks. Feistel networks were first seen commercially in IBM's Lucifer cipher, designed by Horst Feistel and Don Coppersmith in 1973. Feistel networks gained respectability when the U.S. Federal Government adopted the DES (a cipher based on Lucifer, with cha ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Feistel Cipher Diagram En
Feistel is a German surname. Notable people with the surname include: *Horst Feistel (1915–1990), German American cryptographer **Feistel cipher, a construction for designing modern ciphers *Magdalena Feistel (born 1970), Polish tennis player *Gavin Feistel Gavin is a Celtic male given name. It is the Scottish variation of the medieval Welsh name Gawain, meaning 'God send' or 'white hawk/falcon'. Sir Gawain is a knight of King Arthur's Round Table. ''Sir Gawain and the Green Knight'' is an epic poem ... (born 2007), Sigma {{surname, Feistel German-language surnames ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Decryption
In cryptography, encryption (more specifically, encoding) is the process of transforming information in a way that, ideally, only authorized parties can decode. This process converts the original representation of the information, known as plaintext, into an alternative form known as ciphertext. Despite its goal, encryption does not itself prevent interference but denies the intelligible content to a would-be interceptor. For technical reasons, an encryption scheme usually uses a pseudo-random encryption key generated by an algorithm. It is possible to decrypt the message without possessing the key but, for a well-designed encryption scheme, considerable computational resources and skills are required. An authorized recipient can easily decrypt the message with the key provided by the originator to recipients but not to unauthorized users. Historically, various forms of encryption have been used to aid in cryptography. Early encryption techniques were often used in military m ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Thorp Shuffle
''Thorp'' is a Middle English word for a hamlet or small village. Etymology The name can either come from Old Norse ''þorp'' (also ''thorp''), or from Old English (Anglo-Saxon) ''þrop''. There are many place names in England with the suffix "-thorp" or "-thorpe". Those of Old Norse origin are to be found in Northumberland, County Durham, Yorkshire, Lincolnshire, Cambridgeshire, Norfolk, and Suffolk. Those of Anglo-Saxon origin are to be found in southern England from Worcestershire to Surrey. Care must be taken to distinguish the two forms. Variations of the Anglo-Saxon suffix are "-throp", "-thrope", "-trop" and "-trip" (e.g. Adlestrop and Southrope). Old English (Anglo-Saxon) ''þrop'' is cognate with Low-Saxon ''trup''/''trop''/''drup''/''drop'' as in Handrup or Waltrop, Frisian ''terp'', German ''torp'' or ''dorf'' as in Düsseldorf, the 'Village of the river Düssel', and Dutch ''dorp''. It also appears in Lorraine place-names as ''-troff'' such as Grosblieders ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Challenge–response Authentication
In computer security, challenge-response authentication is a family of protocols in which one party presents a question ("challenge") and another party must provide a valid answer ("response") to be authentication, authenticated. The simplest example of a challenge-response protocol is password authentication, where the challenge is asking for the password and the valid response is the correct password. An Adversary (cryptography), adversary who can Network eavesdropping, eavesdrop on a password authentication can authenticate themselves by reusing the intercepted password. One solution is to issue multiple passwords, each of them marked with an identifier. The verifier can then present an identifier, and the prover must respond with the correct password for that identifier. Assuming that the passwords are chosen independently, an adversary who intercepts one challenge-response message pair has no clues to help with a different challenge at a different time. For example, when ot ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Texas Instruments
Texas Instruments Incorporated (TI) is an American multinational semiconductor company headquartered in Dallas, Texas. It is one of the top 10 semiconductor companies worldwide based on sales volume. The company's focus is on developing analog chips and embedded processors, which account for more than 80% of its revenue. TI also produces digital light processing (DLP) technology and education technology products including calculators, microcontrollers, and multi-core processors. Texas Instruments emerged in 1951 after a reorganization of Geophysical Service Incorporated, a company founded in 1930 that manufactured equipment for use in the seismic industry, as well as defense electronics. TI produced the world's first commercial silicon transistor in 1954, and the same year designed and manufactured the first transistor radio. Jack Kilby invented the integrated circuit in 1958 while working at TI's Central Research Labs. TI also invented the hand-held calculator in 1967, and intr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Skipjack (cipher)
In cryptography, Skipjack is a block cipher—an algorithm for encryption—developed by the United States, U.S. National Security Agency (NSA). Initially Classified information, classified, it was originally intended for use in the controversial Clipper chip. Subsequently, the algorithm was declassified. History of Skipjack Skipjack was proposed as the encryption algorithm in a US government-sponsored scheme of key escrow, and the cipher was provided for use in the Clipper chip, implemented in tamper resistance, tamperproof hardware. Skipjack is used only for encryption; the key escrow is achieved through the use of a separate mechanism known as the Clipper chip, Law Enforcement Access Field (LEAF). The algorithm was initially secret, and was regarded with considerable suspicion by many for that reason. It was classified information, declassified on 24 June 1998, shortly after its basic design principle had been discovered independently by the public cryptography community. To ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Oracle Machine
In complexity theory and computability theory, an oracle machine is an abstract machine used to study decision problems. It can be visualized as a black box, called an oracle, which is able to solve certain problems in a single operation. The problem can be of any complexity class. Even undecidable problems, such as the halting problem, can be used. Oracles An oracle machine can be conceived as a Turing machine connected to an oracle. The oracle, in this context, is an entity capable of solving some problem, which for example may be a decision problem or a function problem. The problem does not have to be computable; the oracle is not assumed to be a Turing machine or computer program. The oracle is simply a "black box" that is able to produce a solution for any instance of a given computational problem: * A decision problem is represented as a set ''A'' of natural numbers (or strings). An instance of the problem is an arbitrary natural number (or string). The solution to t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pseudorandom Permutation
In cryptography, a pseudorandom permutation (PRP) is a function that cannot be distinguished from a random permutation (that is, a permutation selected at random with uniform probability, from the family of all permutations on the function's domain) with practical effort. Definition Let ''F'' be a mapping \left\^n \times \left\^s \rightarrow \left\^n. ''F'' is a PRP if and only if * For any K \in \left\^s, F_K is a bijection from \left\^n to \left\^n, where F_K(x)=F(x,K). * For any K \in \left\^s, there is an "efficient" algorithm to evaluate F_K(x) for any x \in \left\^n,. * For all probabilistic polynomial-time distinguishers D: \left, Pr\left(D^(1^n) = 1\right) - Pr\left(D^(1^n) = 1\right) \ < \varepsilon(s), where is chosen uniformly at random and is chosen uniformly at random from the set of permutations on ''n''-bit strings. A pseudorandom permutation family is a collection of pseudorandom permutations, where a specific p ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pseudorandom Function
In cryptography, a pseudorandom function family, abbreviated PRF, is a collection of efficiently-computable functions which emulate a random oracle in the following way: no efficient algorithm can distinguish (with significant advantage) between a function chosen randomly from the PRF family and a random oracle (a function whose outputs are fixed completely at random). Pseudorandom functions are vital tools in the construction of cryptographic primitives, especially secure encryption schemes. Pseudorandom functions are not to be confused with pseudorandom generators (PRGs). The guarantee of a PRG is that a ''single'' output appears random if the input was chosen at random. On the other hand, the guarantee of a PRF is that ''all its outputs'' appear random, regardless of how the corresponding inputs were chosen, as long as the ''function'' was drawn at random from the PRF family. A pseudorandom function family can be constructed from any pseudorandom generator, using, for exampl ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Charles Rackoff
Charles Weill Rackoff is an American cryptologist. Born and raised in New York City, he attended MIT as both an undergraduate and graduate student, and earned a Ph.D. degree in Computer Science in 1974. He spent a year as a postdoctoral scholar at INRIA in France. Rackoff currently works at the University of Toronto. His research interests are in computational complexity theory. For some time now, he has been specializing in cryptography and security protocols. In 1988, he collaborated with Michael Luby in a widely cited analysis of the Feistel cipher construction (one important result shown there is the construction of a strongly pseudo random permutation generator from a pseudo random function generator). Rackoff was awarded the 1993 Gödel Prize for his work on interactive proof systems and for being one of the co-inventors of zero-knowledge proofs. In 2011, he won the RSA Award for Excellence in Mathematics for his various contributions to cryptography. Rackoff's controve ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
