CAST-128 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.

(From: RFC2144)