Cryptographic algorithm as described by Bruce Schneier in "Description of a New Variable-Length Key,
64-Bit Block Cipher (Blowfish). In Fast Software Encryption - Proceedings of the Cambridge Security
Workshop, Cambridge, United Kingdom, Lectures Notes in Computer Science 809, pp. 191-204, Springer Verlag, 1994".
It may be used in ECB, CBC, 8-bit OFB, and 8-bit CFB operation mode.