Anubis  Anubis is a 128bit block cipher that accepts a variablelength key. 
BaseCipher  A basic abstract class to facilitate implementing symmetric key block
ciphers.

Blowfish  Blowfish is a 16round, 64bit Feistel cipher designed by Bruce Schneier. 
Cast5  An implmenetation of the CAST5 (a.k.a. 
CipherFactory  A Factory to instantiate symmetric block cipher instances.

DES  The Data Encryption Standard. 
Khazad  Khazad is a 64bit (legacylevel) block cipher that accepts a 128bit key.

NullCipher  The implementation of a Null block cipher.

Rijndael  Rijndael pronounced Reindaal is the AES. 
Serpent  Serpent is a 32round substitutionpermutation network block cipher,
operating on 128bit blocks and accepting keys of 128, 192, and 256 bits in
length. 
Square  Square is a 128bit key, 128bit block cipher algorithm developed by Joan
Daemen, Lars Knudsen and Vincent Rijmen.

TripleDES  TripleDES, 3DES, or DESede is a combined cipher that uses three
iterations of the Data Encryption Standard cipher to theoretically improve
the security of plain DES, at the cost of speed.

Twofish  Twofish is a balanced 128bit Feistel cipher, consisting of 16 rounds. 