Advanced Encryption Standard: Difference between revisions

Revision as of 22:59, 7 August 2010

Revision as of 13:49, 18 August 2010

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AES is based on a design principle known as a [[Substitution-permutation network|Substitution permutation network]]. It is fast in both [[computer software|software]] and [[hardware]].<ref>{{cite web |url=http://www.schneier.com/paper-twofish-final.pdf |title=The Twofish Team’s Final Comments on AES Selection |author=Bruce Schneier, John Kelsey, Doug Whiting, David Wagner, Chris Hall, Niels Ferguson, Tadayoshi Kohno, Mike Stay |date=May 2000}}</ref> Unlike its predecessor, DES, AES does not use a [[Feistel network]].

AES has a fixed [[block size (cryptography)|block size]] of 128 [[bit]]s and a [[key size]] of 128, 192, or 256 bits, whereas Rijndael can be specified with block and key sizes in any multiple of 32 bits, with a minimum of 128 bits. The blocksize has a maximum of 256 bits, but the keysize has theoretically no theoretical maximum.

AES operates on a 4&times;4 array of bytes, termed the ''state'' (versions of Rijndael with a larger block size have additional columns in the state). Most AES calculations are done in a special [[Finite field arithmetic|finite field]].