See also: Cryptography | Algorithm | Twofish

A symmetric block cipher that can be used as a drop-in replacement for DES or IDEA. It takes a variable-length key, from 32 bits to 448 bits, making it ideal for both domestic and exportable use. Blowfish was designed in 1993 by Bruce Schneier as a fast, free alternative to existing encryption algorithms. Since then it has been analyzed considerably, and it is slowly gaining acceptance as a strong encryption algorithm. Blowfish is unpatented and license-free, and is available free for all uses.

There are no known attacks against Blowfish. Twofish, its successor, is much more complex and also developed by Bruce Schneier under the same unpatented license-free guidelines.


  • Counterpane ( Essentially the blowfish home page.
  • Not Hootie (

TakeDown.NET -> “Blowfish