Cast is encryption algorithm similar to blowfish. It is designed by Stafford Taveres and Carlisle Adams, and name "CAST" represents the first letters of their names. CAST algorithm is gaining more and more popularity. Cast 128 is licence free algorithm available for everyone.
How cast algorithm works?
CAST-128 is a 12- or 16-round Feistel network with a 64-bit block size and a key size of between 40 to 128 bits (but only in 8-bit increments). The full 16 rounds are used when the key size is longer than 80 bits. 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.
CAST-256 is a symmetric cipher designed in accordance with the CAST design
procedure as outlined in [A97]. It is an extension of the CAST-128 cipher and has been submitted as a candidate for NIST’s Advanced Encryption Standard (AES) effort