Certificate Authority

A certificate authority, also called a certification authority or CA, issues digital certificates that associate identities with public keys. A publicly trusted TLS CA checks domain control and applicable identity requirements before signing a website certificate. Clients validate the certificate chain against a trusted root and check the server's proof of the corresponding private key. A CA can delegate signing authority to an intermediate CA. CA trust authenticates an identity under client policy. CA trust does not guarantee that a website's content is honest.