A symmetric block cipher algorithm that takes a variable-length key from 32 bits to 448 bits. Its author, Bruce Schneier, claims that Blowfish is optimized for applications where the key does not change often.
An alternative to DES. The sender and receiver of a message share a single, common key to Encrypt and decrypt the message. As opposed to DES, which has a relatively short key length, Blowfish contains a variable key length, up to 448 bits.