54 䡲 Cyber Forensics Field Manual, Second Edition
the AES, became the offi cial successor to DES in December 2001. AES uses an SKC scheme
called Rijndael, a block cipher designed by Belgian cryptographers, Joan Daemen and
Vincent Rijmen. e algorithm can use a variable block length and key length; the latest
specifi cation allowed any combination of keys lengths of 128, 192, or 256 bits and blocks of
length 128, 192, or 256 bits. NIST initially selected Rijndael in October 2000 and formal
adoption as the AES standard came in December 2001. FIPS PUB 197 [http://csrc.nist.gov/
publications/fi ps/fi ps197/fi ps-197.pdf ]describes a 128-bit block cipher employing a 128-,
192-, or 256-bit key.
CAST-128/256: CAST-128, is a DES–like substitution-p