CAST5
Published in
3 min readJul 2, 2023
CAST5 (or CAST-128) was created by Carlisle Adams and Stafford Tavares in 1996. It defines a symmetric key method that has a 64-bit block size, and key sizes from 40 bits up to 128 bits (in jumps of 8 bits). Typically any key less than 80 bits would be seen as being insecure. It uses a 12- or 16-round Feistel cipher. The 16-round version is used for keys for 80 bits and above. It has been standardized in RFC2612 [here]:
