|Type:||Symmetric block cipher algorithm.|
|Block size:||64 bits (CAST-128).|
128 bits (CAST-256).
|Key size:||40 to 128 bits in 8-bit increments (CAST-128).
128, 160, 192, 224 or 256 bits (CAST-256).
|Working groups:||smime, S/MIME Mail Security.|
The CAST encryption algorithm is a DES-like Substitution-Permutation Network (SPN) cryptosystem which appears to have good resistance to differential cryptanalysis, linear cryptanalysis, and related-key cryptanalysis. This cipher also possesses a number of other desirable cryptographic properties, including avalanche, Strict Avalanche Criterion (SAC), Bit Independence Criterion (BIC), no complementation property, and an absence of weak and semi-weak keys. It thus appears to be a good candidate for general-purpose use throughout the Internet community wherever a cryptographically-strong, freely-available encryption algorithm is required.
[RFC 2144] The CAST-128 Encryption Algorithm.
[RFC 2612] The CAST-256 Encryption Algorithm.
[RFC 2984] Use of the CAST-128 Encryption Algorithm in CMS.