X.509 Certificate

An X.509 certificate is a high-security credential used to encrypt, sign and authenticate transmissions, files and other data.  X.509 certificates secure SSL/TLS channels, authenticate SSL/TLS servers (and sometimes clients), encrypt/sign SMIME, AS1, AS2, AS3 and some “secure zip” payloads, and provide non-repudiation to the AS1, AS2 and AS3 protocols. The relative strength of various certificates[..]