X.509 Certificate

An X.509 certificate is a standard-format digital document that binds a public key to a verified identity, signed by a certificate authority, with a validity period, serial number, and revocation pointers. Defined by ITU-T X.509 and profiled for the internet in IETF RFC 5280, it is the credential format used in maritime public-key infrastructure: electronic bills of lading, the SSAS, and secure machine-to-machine links. A relying party checks the issuer’s signature, the validity dates, and whether the certificate appears on a revocation list or fails OCSP.