What is a digital certificate?

A digital certificate is an electronic "credit card" that establishes your credentials when doing business or other transactions on the internet. The certificate is issued by a certificate authority (CA). It contains:

• your name,
• a serial number,
• expiration dates,
• a copy of the certificate holder's public key (used for encrypting messages and digital signatures), and
• the digital signature of the certificate-issuing authority.

With this digital information, a recipient can verify that the certificate is real. Digital certificates are kept in registries, so that authenticating users can look up other users' public keys.