Libmcrypt is the library which implements all the algorithms and modes found in mcrypt.

libmcrypt supports the algorithms: blowfish, twofish, des, tripledes, 3-way, safer-sk64, safer-sk128, safer+, loki97, gost, rc2, rc6, mars, idea, rijndael-128, rijndael-192, serpent, rijndael-256, cast-128 (known as cast5), cast-256, arcfour, enigma, panama, xtea and wake. block algorithms can be used in: cbc, ecb, cfb and ofb (8 bit and n bit, where n is the size of the algorithm's block length).

more information can be found at the libmcrypt homepage http://mcrypt.sourceforge.net/ .