Description:

Mcrypt is a simple crypting program, a replacement for the old unix crypt(1).

Mcrypt uses the following symmetric (block) algorithms:
+ DES: standard DED with 56 bit key and 64 bit block;
+ 3DES(Triple DES): DES but with multiple (triple) encryption;
+ CAST-128: extended CAST with 128bit key and 64bit block size;
+ CAST-256: extended CAST-128 with 128bit key and up to 256bit block size;
+ xTEA: extended TEA with 128bit key size and 64bit block size;
+ 3-WAY: 3way by Joan Daemen, uses key and block size of 96 bits;
+ BLOWFISH: standard Blowfish by Bruce Schneier, uses key up to 448 bits;
+ TWOFISH: standard Twofish, uses 128bit block size and 128,192,256 bit key size;
+ LOKI97: uses 128bit block size and 256bit key size;
+ RC2: standard RC2 as described in RFC2268, uses 64bit block size and key size from 8 to 1024 bits;
+ RC4: alternative implementation (ARCFOUR), has a maximum key of 2048 bits;
+ RIJNDAEL: AES winner, has a variable block length and key length;
+ PANAMA: designed by Joan Daemen and Craig Clapp;
+ WAKE: designed by David J. Wheeler;
+ SERPENT: AES candidate, uses 128bit block size;
+ UNIX crypt: encient "Enigma" crypt (not recommended);
+ GOST: uses 256bit key and a 64bit block;
+ SAFER: strengthened SAFER with 64bit or 128bit key size;
+ SAFER+: uses 128bit block size and 128, 192 and 256 bits key size.
The default algorithm is Twofish.

All the block algorithms above support following modes of encryption:
ECB, CBC, CFB, OFB, nOFB; default mode is CBC.