What is Twofish?
Twofish is a symetric key block cipher. Symetric means that the data is encrypted and decrypted with a matching password. If you encrypt information with one password, those looking to see the decrypted information will need that same password. Additional information can be found here. The Blackbird implementation of Twofish comes with a few changes from the freely available version. For Blackbird, the data beyond 16 bytes (characters) is “Cypher Block Chained” (CBC) to accomodate varying data lengths.
