4.1.2 Authentication using OpenPGP keys

OpenPGP keys also contain public parameters of a public key algorithm, and signatures from several other parties. Depending on whether a signer is trusted the key is considered trusted or not. GnuTLS’s OpenPGP authentication implementation is based on the [TLSPGP]

More information on the OpenPGP trusted model is provided in The OpenPGP trust model. For a more detailed introduction to OpenPGP and GnuPG see [GPGH]