# Information About Public Key Infrastructure Certificates

A certificate is an electronic document that you use to identify a server, a company, or some other entity and to associate that identity with a public key.

Certificate authority (CA) are entities that validate identities and issue certificates. The certificate that the CA issues binds a particular public key to the name of the entity that the certificate identifies (such as the name of a server or device). Only the public key that the certificate certifies works with the corresponding private key that is possessed by the entity that the certificate identifies. Certificates help prevent the use of fake public keys for impersonation.