SnapGear 2.0.1 - Manual (Page 180)

176
x.509 Certificates An x.509 certificate includes the format of the certificate, the serial
number of the certificate, the algorithm used to sign the certificate, the
name of the CA that issued the certificate, the name and public key of
the entity requesting the certificate, and the CA's signature.x.509
certificates are used to authenticate the remote party against a
Certificate Authority's (CA) certificate. The CA certificate must have
signed the local certificates that are used for tunnel authentication.
Certificates need to be uploaded into the CyberGuard SG appliance
before a tunnel can be configured to use them (see Certificate
Management).