Twofish encryption algorithm (original) (raw)

Twofish is a symmetric key block cipher with a block size of 128 bits and key sizes up to 256 bits. It was one of the five finalists of the AES contest, but was not selected for standardisation.

Twofish's distinctive features are the use of pre-computed key-dependent S-boxes, and a relatively complex key schedule. On most software platforms Twofish is slightly slower than AES for 128-bit keys, but somewhat faster for 256-bit keys.

As of Sept. 2002 there is no known attack on Twofish more efficient than brute force key search.

Publications:

• The Twofish Encryption Algorithm, by Bruce Schneier, John Kelsey, Doug Whiting, David Wagner, Chris Hall, Niels Ferguson. Wiley ISBN 0-471-35381-7, 1999

External links:

• Twofish web page with full specifications, free source code, and other Twofish resources.