CAST-128

The algorithm was created in 1996 by Carlisle Adams and Stafford Tavares using the CAST design procedure.

According to some sources, the CAST name is based on the initials of its inventors, though Bruce Schneier reports the authors' claim that "the name should conjure up images of randomness".

[3] Components include large 8×32-bit S-boxes based on bent functions, key-dependent rotations, modular addition and subtraction, and XOR operations.

There are three alternating types of round function, but they are similar in structure and differ only in the choice of the exact operation (addition, subtraction or XOR) at various points.

Although Entrust holds a patent on the CAST design procedure, CAST-128 is available worldwide on a royalty-free basis for commercial and non-commercial uses.