NationMaster - Encyclopedia: Substitution box

In cryptography, a substitution box (or S-box) is a basic component of symmetric key algorithms. In block ciphers, they are typically used to obscure the relationship between the plaintext and the ciphertext — Shannon's property of confusion. In many cases, the S-boxes are carefully chosen to resist cryptanalysis. See also: Topics in cryptography The security of all practical encryption schemes remains unproven, both for symmetric and asymmetric schemes. ... A symmetric-key algorithm is an algorithm for cryptography that uses the same cryptographic key to encrypt and decrypt the message. ... In cryptography, a block cipher is a type of symmetric key cipher which operates on groups of bits of a fixed length, termed blocks. ... In cryptography, plaintext is information used as input to an encryption algorithm; the output is termed ciphertext. ... This article is about algorithms for encryption and decryption. ... Claude Elwood Shannon (April 30, 1916 _ February 24, 2001) has been called the father of information theory, and was the founder of practical digital circuit design theory. ... In cryptography, confusion and diffusion are two properties of the operation of a secure cipher which were identified by Shannon in his paper, Communication Theory of Secrecy Systems published in 1949. ... For the Game Boy Advance cheat device, see CodeBreaker (Game Boy) Cryptanalysis (from the Greek kryptós, hidden, and analýein, to loosen or to untie) is the study of methods for obtaining the meaning of encrypted information without access to the secret information which is normally required to do so. ...

In general, an S-box takes some number of input bits, m, and transforms them into some number of output bits, n: an m×n S-box, implemented as a lookup table. Fixed tables are normally used, as in the Data Encryption Standard (DES), but in some ciphers the tables are generated dynamically from the key; e.g. the Blowfish and the Twofish encryption algorithms. A bit (abbreviated b) is the most basic information unit used in computing and information theory. ... In computer science, a lookup table is a data structure, usually an array or associative array, used to replace a runtime computation with a simpler lookup operation. ... General Designer(s) IBM First published 1975 (January 1977 as the standard) Derived from Lucifer (cipher) Cipher(s) based on this design Triple DES, G-DES, DES-X, LOKI89, ICE Algorithm detail Block size(s) 64 bits Key size(s) 56 bits Structure Feistel network Number of rounds 16 Best... This article is about algorithms for encryption and decryption. ... A key is a piece of information that controls the operation of a cryptography algorithm. ... General Designer(s) Bruce Schneier First published 1993 Derived from - Cipher(s) based on this design - Algorithm detail Block size(s) 64 bits Key size(s) 32-448 bits in steps of 8 bits; default 128 bits Structure Feistel network Number of rounds 16 Best cryptanalysis Four rounds of Blowfish... In cryptography, Twofish is a symmetric key block cipher with a block size of 128 bits and key sizes up to 256 bits. ...

Given a 6-bit input, the 4-bit output is found by selecting the row using the outer two bits, and the column using the inner four bits. For example, an input "011011" has outer bits "01" and inner bits "1101"; the corresponding output would be "1001".

The S-boxes of DES were the subject of intense study for many years out of a concern that a backdoor — a vulnerability known only to its designers — might have been planted in the cipher. The S-box design criteria were eventually published (Don Coppersmith, 1994) after the public rediscovery of differential cryptanalysis, showing that they had been carefully tuned to increase resistance against this specific attack. Other research had already indicated that even small modifications to an S-box could significantly weaken DES. A backdoor in a computer system (or a cryptosystem, or even in an algorithm) is a method of bypassing normal authentication or obtaining remote access to a computer, while intended to remain hidden to casual inspection. ... For the Game Boy Advance cheat device, see CodeBreaker (Game Boy) Cryptanalysis (from the Greek kryptós, hidden, and analýein, to loosen or to untie) is the study of methods for obtaining the meaning of encrypted information without access to the secret information which is normally required to do so. ... Don Coppersmith is a cryptographer and mathematician who was involved in the design of the Data Encryption Standard block cipher at IBM. He has also worked on algorithms for computing discrete logarithms, the cryptanalysis of RSA, methods for rapid matrix multiplication and IBMs MARS cipher, In 1972, Coppersmith obtained... Differential cryptanalysis is a general form of cryptanalysis applicable primarily to block ciphers, but also to stream ciphers and cryptographic hash functions. ...

There has been a great deal of research into the design of good S-boxes, and much more is understood about their use in block ciphers than when DES was released.

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In mathematics, a Boolean function is usually a function F(b1, b2, ... , bn) of a number n of Boolean variables bi from the two-element Boolean algebra {0,1}, and such that F also takes values in {0, 1}. A function on a general domain of a function taking values... In cryptography, a substitution cipher is a method of encryption by which units of plaintext are substituted with ciphertext according to a regular system; the units may be single letters (the most common), pairs of letters, triplets of letters, mixtures of the above, and so forth. ...

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Categories: Cryptography In cryptography, a block cipher is a type of symmetric key cipher which operates on groups of bits of a fixed length, termed blocks. ... In cryptography, 3-Way is a block cipher designed in 1994 by Joan Daemen, who also (with Vincent Rijmen) designed Rijndael, the winner of NISTs Advanced Encryption Standard (AES) contest. ... General Designer(s) Vincent Rijmen and Joan Daemen First published 1998 Derived from Square (cipher) Cipher(s) based on this design Crypton (cypher), Anubis (cipher), GRAND CRU Algorithm detail Block size(s) 128 bits note Key size(s) 128, 192 or 256 bits note Structure Substitution-permutation network Number of... Akelarre is a block cipher proposed in 1996, and combined features from IDEA and RC5. ... General Designer(s) Bruce Schneier First published 1993 Derived from - Cipher(s) based on this design - Algorithm detail Block size(s) 64 bits Key size(s) 32-448 bits in steps of 8 bits; default 128 bits Structure Feistel network Number of rounds 16 Best cryptanalysis Four rounds of Blowfish... In cryptography, Camellia is a block cipher that has been evaluated favorably by several organisations, including the European Unions NESSIE project (a selected algorithm), and the Japanese CRYPTREC project (a recommended algorithm). ... The following article is about the block cipher. ... In cryptography, CAST-256 (or CAST6) is a block cipher published in June 1998 and submitted as a candidate for the Advanced Encryption Standard (AES). ... In cryptography, the Cellular Message Encryption Algorithm (CMEA) is a block cipher which was used for securing mobile phones in the United States. ... In cryptography, DEAL (Data Encryption Algorithm with Larger blocks) is a block cipher derived from the Data Encryption Standard (DES). ... General Designer(s) IBM First published 1975 (January 1977 as the standard) Derived from Lucifer (cipher) Cipher(s) based on this design Triple DES, G-DES, DES-X, LOKI89, ICE Algorithm detail Block size(s) 64 bits Key size(s) 56 bits Structure Feistel network Number of rounds 16 Best... In cryptography, DES-X (or DESX) is a variant on the DES (Data Encryption Standard) block cipher intended to increase the complexity of a brute force attack using a technique called key whitening. ... There have been several different revisions of FEAL, though all are Feistel ciphers, and make use of the same basic round function and operate on a 64-bit block. ... General Designer(s) Serge Vaudenay, Pascal Junod First published 2002 Derived from IDEA Cipher(s) based on this design None Algorithm detail Block size(s) 64, 128 bits Key size(s) 128, 256 bits Structure Lai-Massey scheme Number of rounds 16 Best cryptanalysis External cryptanalysis conducted by David Wagner... Frogs are amphibians in the Order Anura, which includes frogs and toads. ... In cryptography, the Generalized DES Scheme (G-DES or GDES) is a variant of the DES block cipher designed to speed-up the encryption. ... In cryptography, GOST (Russian ГОСТ) (GOsudarstvennyi STandard, Russian for Government Standard) is a symmetric key block cipher published in 1990 as the Soviet standard (GOST 28147-89). ... In cryptography, ICE (Information Concealment Engine) is a block cipher published by Kwan in 1997. ... In cryptography, the International Data Encryption Algorithm (IDEA) is a block cipher designed by Xuejia Lai and James L. Massey of ETH-Zürich and was first described in 1991. ... Kasumi is a Japanese given name. ... Khazad redirects here. ... In cryptography, Khufu and Khafre are two block ciphers designed by Ralph Merkle in 1989 while working at Xeroxs Palo Alto Research Center. ... This picture, from an 18th century Icelandic manuscript, shows Loki with his invention - the fishing net. ... In cryptography, LOKI97 is a block cipher which was a candidate in the Advanced Encryption Standard competition. ... In cryptography, Lucifer was the name given to several of the earliest civilian block ciphers, developed by Horst Feistel and his colleagues at IBM. Lucifer was a direct precursor to the Data Encryption Standard. ... In cryptography, MacGuffin is a block cipher created in 1994 by Bruce Schneier and Matt Blaze at a Fast Software Encryption workshop. ... In cryptography, Madryga is a block cipher created in 1984 by W. E. Madryga. ... In cryptography, MAGENTA is a symmetric key block cipher developed by Deutsche Telekom. ... Mars, with polar ice caps visible. ... In cryptography, MISTY1 (or MISTY-1) is a block cipher designed in 1995 by Mitsuru Matsui for Mitsubishi Electric. ... In cryptography, MMB (Modular Multiplication-based Block cipher) is a block cipher designed by Joan Daemen as an improved replacement for the IDEA cipher. ... In cryptography, NewDES is a symmetric key block cipher. ... In cryptography, RC2 is a block cipher designed by Ron Rivest in 1987. ... General Designer(s) Ron Rivest First published 1994 Derived from - Cipher(s) based on this design RC6, Akelarre Algorithm detail Block size(s) 32, 64 or 128 bits (64 suggested) Key size(s) 0 to 2040 bits (128 suggested) Structure Feistel network Number of rounds 12 suggested originally Best cryptanalysis... In cryptography, RC6 is a symmetric key block cipher derived from RC5. ... In cryptography, REDOC II and REDOC III are block ciphers designed by Michael Wood for Cryptech Inc and are optimised for use in software. ... Red Pike is a classified United Kingdom government cipher, proposed for use by the National Health Service by GCHQ, but designed for a broad range of applications in the British government [1]. Little is publicly known about Red Pike, except that it is a block cipher with a 64-bit... Uplandia Regiment, or Upplands regemente, also S 1, is a Swedish Army signaling regiment that traces its origins back to the 19th Century. ... This article is about the encryption algorithm. ... A SeeD is a term given to mercenaries trained and employed by Balamb Garden in the Final Fantasy VIII video game. ... Serpent is a symmetric key block cipher which was a finalist in the Advanced Encryption Standard contest, where it came second to Rijndael. ... SHACAL is a 160-bit block cipher based on the cryptographic hash function SHA-1. ... Orders See Classification and Shark taxonomy Sharks are a group (superorder Selachimorpha) of fish, with a full cartilaginous skeleton, a streamlined body plan with between 5 and 7 gill slits along the sides (most often) or side of the head (the first modified slit is behind the eye and called... In cryptography, Skipjack is a block cipher — an algorithm for encryption — developed by the US National Security Agency (NSA). ... In cryptography, Square (sometimes written SQUARE) is a block cipher invented by Joan Daemen and Vincent Rijmen. ... Two rounds of the TEA block cipher In cryptography, the Tiny Encryption Algorithm (TEA) is a block cipher notable for its simplicity of description and implementation (typically a few lines of code). ... In cryptography, Triple DES (also 3DES) is a block cipher formed from the Data Encryption Standard (DES) cipher. ... In cryptography, Twofish is a symmetric key block cipher with a block size of 128 bits and key sizes up to 256 bits. ... General Designer(s) Roger Needham and David Wheeler First published 1997 Derived from Tiny Encryption Algorithm (TEA) Cipher(s) based on this design - Algorithm detail Block size(s) 64 bits Key size(s) 128 bits Structure Feistel network Number of rounds variable; recommended 64 Feistel rounds; 32 cycles Best cryptanalysis... In cryptography, a Feistel cipher is a block cipher with a particular structure, named after IBM cryptographer Horst Feistel; it is also commonly known as a Feistel network. ... The key-schedule of DES In cryptography, the algorithm for computing the subkeys for each round in a product cipher from the encryption (or decryption) key is called the key schedule. ... In cryptography, a product cipher is a popular type of block cipher that works by executing in sequence a number of simple transformations such as substitution, permutation, and modular arithmetic. ... In cryptography, a substitution box (or S-box) is a basic component of symmetric key algorithms. ... Wikipedia does not yet have an article with this exact name. ... The EFFs US$250,000 DES cracking machine contained over 18,000 custom chips and could brute force a DES key in a matter of days — the photograph shows a DES Cracker circuit board fitted with several Deep Crack chips In cryptanalysis, a brute force attack is a method... In cryptography, linear cryptanalysis is a general form of cryptanalysis based on finding affine approximations to the action of a cipher. ... Differential cryptanalysis is a general form of cryptanalysis applicable primarily to block ciphers, but also to stream ciphers and cryptographic hash functions. ... For the Game Boy Advance cheat device, see CodeBreaker (Game Boy) Cryptanalysis (from the Greek kryptós, hidden, and analýein, to loosen or to untie) is the study of methods for obtaining the meaning of encrypted information without access to the secret information which is normally required to do so. ... In cryptography, mod n cryptanalysis is an attack applicable to block and stream ciphers. ... New Scientist magazine featured the XSL attack in July 2003 with an article billed as Cipher crisis: the end of internet privacy. In cryptography, the XSL attack is a method of cryptanalysis for block ciphers. ... On January 2, 1997 the National Institute of Standards and Technology, or NIST, called for cryptographers to propose a new standard block cipher for United States Government use in non-classified but sensitive applications. ... CRYPTREC is the Cryptography Research and Evaluation Committee set up by the Japanese Government to evaluate and recommend cryptographic techniques for government and industrial use. ... NESSIE (New European Schemes for Signatures, Integrity and Encryption) was a European research project funded from 2000–2003 to identify secure cryptographic primitives. ... This article is about cryptography; for other meanings, see snowball effect. ... In modern cryptography, symmetric key ciphers are generally divided into stream ciphers and block ciphers. ... In cryptography, an initialization vector (IV) is a block of bits that is combined with the first block of data in any of several modes of a block cipher. ... In cryptography, the key size (alternatively key length) is a measure of the number of possible keys which can be used in a cipher. ... In cryptography, a block cipher operates on blocks of fixed length, often 64 or 128 bits. ... In cryptanalysis, the piling-up lemma is a principle used in linear cryptanalysis to construct linear approximations to the action of block ciphers. ... In cryptography, a weak key is a key which when used with a specific cipher, makes the cipher behave in some undesirable way. ...

Encyclopedia > Substitution box

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