Home > CAST-128

In cryptography, CAST-128 (alternatively CAST5) is a block cipher used in a number of products, notably as the default cipher in some versions of GPG and PGP. It has also been approved for Canadian government use by the Communications Security Establishment. The algorithm was created in 1996 by Carlisle Adams and Stafford Tavares using the CAST design procedure; another member of the CAST family of ciphers, CAST-256 (a former AES candidate) was derived from CAST-128. According to some sources, the "CAST" name is based on the initials of its inventors, though Bruce Schneier reports the authors' claim that "the name should conjure up images of randomness" (Schneier, 1996).

CAST-128 is a 12- or 16-round Feistel network with a 64-bit block size and a key size of between 40 to 128 bitThis article is about the unit of information, see Bit (disambiguation) for other meanings. A bit (abbreviated b is the most basic information unit used in computing and information theory. A single bit (short for b inary dig it is a zero or a one, or a ts (but only in 8-bit increments). The full 16 rounds are used when the key size is longer than 80 bits. Components include large 8×32-bit S-boxes based on bent function s, key-dependent rotations, modularModular arithmetic Group theory In mathematics, modular arithmetic is a system of arithmetic for certain equivalence classes of integers, called congruence classes . In modular arithmetic, numbers 'wrap around' after they reach a certain value (the modulu addition and subtraction, and XOR operations. There are three alternating types of round function, but they are similar in structure and differ only in the choice of the exact operation (addition, subtraction or XOR) at various points.

Although EntrustEntrust is a Canadian company, a spinoff of Nortel. Its central product is a Public Key Infrastructure (PKI), which Entrust uses as the basis for the development of secure messaging, identity management, and authentication solutions. Entrust is public tra holds a patentA patent is a set of exclusive rights granted by a government to an inventor or applicant for a limited amount of time (normally 20 years from the filing date). The term "patent" originates from the term patere which means to lay open (to public inspectio on the CAST design procedure, CAST-128 is available worldwide on a royalty-free basis for commercial and non-commercial uses.

1 See also

• BlowfishIn cryptography, Blowfish is a symmetric key, secret key, block cipher designed in 1993 by Bruce Schneier and is included in a large number of cipher-suites and encryption products. Schneier intended it as a general-purpose algorithm to replace the aging

2 References

• C.M. Adams. (1997). "Constructing Symmetric Ciphers Using the CAST Design Procedure", Designs, Codes, and Cryptography, 12(3), pp. 283–316.
• C.M. Adams, "CAST Design Procedure Addendum".
• Bruce Schneier, 1996, Applied Cryptography, 2nd edition. John Wiley & Sons. pp334–335. BooksEnthsiast.com