Web and XML Glossary

Certificates are digital documents attesting to the binding of a public key to an individual or other entity. They allow verification of the claim that a given public key does in fact belong to a given individual. Certificates help prevent someone from using a phony key to impersonate someone else. In their simplest form, Certificates contain a public key and a name. As commonly used, a Certificate also contains an expiration date, the name of the CA that issued the Certificate, a serial number, and perhaps other information. Most importantly, it contains the digital signature of the certificate issuer. The most widely accepted format for certificates is X.509, thus, Certificates can be read or written by any application complying with X.509.