What is a Certification Authority (CA)?

A Certification Authority (CA) is an entity that digitally signs each SSL Certificate issued. Each browser contains a list of CAs to be trusted. When a secure connection is created, the browser verifies that the server certificate was issued by a trusted CA. If the CA is not trusted, a warning will appear. CAs must undergo annual security audits (such as WebTrust for Certification Authorities) to be included in the list of web browser trusted authorities.