General Twofish The Twofish algorithm Bruce Schneier 1998 Blowfish, SAFER, Square AES finalist 128, 192 or 256 bits 128 bits Feistel network 16 Truncated differential cryptanalysis requiring roughly 251 chosen plaintexts. Bruce Schneier (born 15 January 1963) is an American Cryptographer, Computer security specialist and Writer. In Cryptography, Blowfish is a keyed symmetric Block cipher, designed in 1993 by Bruce Schneier and included in a large number of In Cryptography, SAFER ( Secure And Fast Encryption Routine) is the name of a family of Block ciphers designed primarily by James Massey (one of In Cryptography, Square (sometimes written SQUARE) is a Block cipher invented by Joan Daemen and Vincent Rijmen The Advanced Encryption Standard (AES the Block cipher ratified as a standard by National Institute of Standards and Technology of the United States (NIST was In Cryptography, key size or key length is the size (usually measured in bits or bytes of the key used in a cryptographic algorithm (such as a Cipher In modern Cryptography, symmetric key Ciphers are generally divided into Stream ciphers and Block ciphers Block ciphers operate on a In Cryptography, a Feistel cipher is a symmetric structure used in the construction of Block ciphers named after the German IBM cryptographer Horst Cryptanalysis (from the Greek kryptós, "hidden" and analýein, "to loosen" or "to untie" is the study of methods for In Cryptography, truncated differential cryptanalysis is a generalization of Differential cryptanalysis, an attack against Block ciphers Lars Knudsen [1]

In cryptography, Twofish is a symmetric key block cipher with a block size of 128 bits and key sizes up to 256 bits. Cryptography (or cryptology; from Greek grc κρυπτός kryptos, "hidden secret" and grc γράφω gráphō, "I write" Symmetric-key algorithms are a class of Algorithms for Cryptography that use trivially related often identical Cryptographic keys for both decryption In Cryptography, a block cipher is a symmetric key Cipher which operates on fixed-length groups of Bits termed blocks, with an In modern Cryptography, symmetric key Ciphers are generally divided into Stream ciphers and Block ciphers Block ciphers operate on a A bit is a binary digit, taking a value of either 0 or 1 Binary digits are a basic unit of Information storage and communication In Cryptography, key size or key length is the size (usually measured in bits or bytes of the key used in a cryptographic algorithm (such as a Cipher It was one of the five finalists of the Advanced Encryption Standard contest, but was not selected for standardisation. The Advanced Encryption Standard (AES the Block cipher ratified as a standard by National Institute of Standards and Technology of the United States (NIST was Twofish is related to the earlier block cipher Blowfish. In Cryptography, Blowfish is a keyed symmetric Block cipher, designed in 1993 by Bruce Schneier and included in a large number of

Twofish's distinctive features are the use of pre-computed key-dependent S-boxes, and a relatively complex key schedule. 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 In Cryptography, the so-called Product ciphers are a certain kind of ciphers where the (de-ciphering of data is done in "rounds" One half of an n-bit key is used as the actual encryption key and the other half of the n-bit key is used to modify the encryption algorithm (key-dependent S-boxes). Twofish borrows some elements from other designs; for example, the pseudo-Hadamard transform (PHT) from the SAFER family of ciphers. The pseudo-Hadamard transform is a reversible transformation of a bit string that provides cryptographic diffusion. In Cryptography, SAFER ( Secure And Fast Encryption Routine) is the name of a family of Block ciphers designed primarily by James Massey (one of Twofish uses the same Feistel structure as DES. In Cryptography, a Feistel cipher is a symmetric structure used in the construction of Block ciphers named after the German IBM cryptographer Horst The Data Encryption Standard ( DES) is a Cipher (a method for Encrypting information selected by NBS as an official Federal Information

On most software platforms Twofish is slightly slower than Rijndael (the chosen algorithm for Advanced Encryption Standard) for 128-bit keys, but somewhat faster for 256-bit keys. In Cryptography, the Advanced Encryption Standard ( AES) also known as Rijndael, is a Block cipher adopted as an Encryption In Cryptography, the Advanced Encryption Standard ( AES) also known as Rijndael, is a Block cipher adopted as an Encryption In Cryptography, a key is a piece of information (a Parameter) that determines the functional output of a cryptographic algorithm [2]

Twofish was designed by Bruce Schneier, John Kelsey, Doug Whiting, David Wagner, Chris Hall, and Niels Ferguson; the "extended Twofish team" who met to perform further cryptanalysis of Twofish and other AES contest entrants included Stefan Lucks, Tadayoshi Kohno, and Mike Stay. Bruce Schneier (born 15 January 1963) is an American Cryptographer, Computer security specialist and Writer. John Kelsey is a Cryptographer currently working at NIST. His research interests include Cryptanalysis and design of Symmetric cryptography For the entomologist see David L Wagner David A Wagner ( 1974) is an Associate Professor of Computer Science Christopher (Chris Hall is an American Cryptographer and Mathematician. Niels Ferguson is a Dutch cryptographic Engineer and consultant who currently works for Microsoft. Stefan Lucks is a researcher in the fields of Communications security and Cryptography.

The Twofish cipher has not been patented and the reference implementation has been placed in the public domain. A patent is a set of Exclusive rights granted by a State to an inventor or his assignee for a fixed period of time in exchange for a disclosure of an In Computing, a reference implementation (or less frequently sample implementation or model implementation) is a software example of a Specification The public domain is a range of abstract materials &ndash commonly referred to as Intellectual property &ndash which are not owned or controlled by anyone As a result, the Twofish algorithm is free for anyone to use without any restrictions whatsoever. However, Twofish has seen less widespread usage than Blowfish, which has been available for a longer period of time. In Cryptography, Blowfish is a keyed symmetric Block cipher, designed in 1993 by Bruce Schneier and included in a large number of

## Cryptanalysis

As of 2008, the best published cryptanalysis on the Twofish block cipher is a truncated differential cryptanalysis of the full 16-round version. 2008 ( MMVIII) is the current year in accordance with the Gregorian calendar, a Leap year that started on Tuesday of the Common In Cryptography, truncated differential cryptanalysis is a generalization of Differential cryptanalysis, an attack against Block ciphers Lars Knudsen The paper claims that the probability of truncated differentials is 2-57. 3 per block and that it will take roughly 251 chosen plaintexts (32 PiB worth of data) to find a good pair of truncated differentials. A pebibyte (a contraction of pe ta bi nary byte) is a unit of Information or Computer storage, abbreviated PiB. [1]

Bruce Schneier responds in a 2005 blog entry that this paper does not present a full cryptanalytic attack, but only some hypothesized differential characteristics: "But even from a theoretical perspective, Twofish isn't even remotely broken. There have been no extensions to these results since they were published" in 2000. [3]

## References

1. ^ a b Shiho Moriai, Yiqun Lisa Yin (2000). "Cryptanalysis of Twofish (II)" (PDF). Retrieved on 2006-08-13. Year 2006 ( MMVI) was a Common year starting on Sunday of the Gregorian calendar. Events 3114 BC - According to the Lounsbury correlation the start of the Maya calendar.
2. ^ Bruce Schneier, Doug Whiting (2000-04-07). 2000 ( MM) was a Leap year that started on Saturday of the Common Era, in accordance with the Gregorian calendar. Events 529 - First draft of Corpus Juris Civilis (a fundamental work in Jurisprudence) is issued by Eastern Roman Emperor "A Performance Comparison of the Five AES Finalists" (PDF/PostScript). PostScript ( PS) is a dynamically typed concatenative Programming language created by John Warnock and Charles Geschke in 1982 Retrieved on 2006-08-13. Year 2006 ( MMVI) was a Common year starting on Sunday of the Gregorian calendar. Events 3114 BC - According to the Lounsbury correlation the start of the Maya calendar.
3. ^ Schneier, Bruce (2005-11-23). Bruce Schneier (born 15 January 1963) is an American Cryptographer, Computer security specialist and Writer. Year 2005 ( MMV) was a Common year starting on Saturday (link displays full calendar of the Gregorian calendar. Events 800 - Charlemagne arrives at Rome to investigate the alleged crimes of Twofish Cryptanalysis Rumors. Schneier on Security blog. Retrieved on 2006-11-28. Year 2006 ( MMVI) was a Common year starting on Sunday of the Gregorian calendar. For the town in Argentina, see 28 de Noviembre. Events
• Bruce Schneier, John Kelsey, Doug Whiting, David Wagner, Chris Hall, Niels Ferguson (1998-06-15). Year 1998 ( MCMXCVIII) was a Common year starting on Thursday (link will display full 1998 Gregorian calendar) Events 763 BC - Assyrians record a Solar eclipse that will be used to fix the Chronology of Mesopotamian history "The Twofish Encryption Algorithm" (PDF/PostScript). PostScript ( PS) is a dynamically typed concatenative Programming language created by John Warnock and Charles Geschke in 1982 Retrieved on 2007-03-04. Year 2007 ( MMVII) was a Common year starting on Monday of the Gregorian calendar in the 21st century. Events 51 - Nero, later to become Roman Emperor, is given the title Princeps iuventutis (head of the youth
• Bruce Schneier, John Kelsey, Doug Whiting, David Wagner, Chris Hall, Niels Ferguson (1999-03-22). The Twofish Encryption Algorithm: A 128-Bit Block Cipher. New York City: John Wiley & Sons. The City of New York John Wiley & Sons Inc, also referred to as Wiley, is a global Publishing company that markets its products to professionals and consumers students and instructors ISBN 0-471-35381-7.