+When signatures are computed in SILC the computing of the signature is
+represented as sign(). The signature computing procedure is dependent
+of the public key algorithm, and the public key or certificate encoding.
+When using SILC public key the signature is computed as described in
+previous section for RSA and DSS keys. When using SSH2 public keys
+the signature is computed as described in [SSH-TRANS]. When using
+X.509 version 3 certificates the signature is computed as described
+in [PKCS7]. When using OpenPGP certificates the signature is computed
+as described in [PGP].
+