Twofish is a symmetric algorithm for encryption and decryption of data. "Symmetric" means that the same key is used for both encryption and decryption. Twofish is unpatented, and the source code is uncopyrighted and license-free; it is free for all uses. It was one of the five [Advanced Encryption Standard] AES finalists.

See [1] for more information about the design of the Twofish algorithm.

See Twofish in Tcl for an implementation in Tcl.

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