The salt, or often called implicit nonce, varies between AEAD algorithms and
their use in protocols. For IKE and ESP, GCM uses 4 bytes, while CCM uses
3 bytes. With TLS, however, AEAD mode uses 4 bytes for both GCM and CCM.
Our GCM backends currently support 4 bytes and CCM 3 bytes only. This is fine
until we go for CCM mode support in TLS, which requires 4 byte nonces.
libstrongswan.crypto.test.required to require at least one test vector to use an algorithm
libstrongswan.crypto.test.rng_true to run RNG tests on RNG_TRUE quality
Andreas Steffen