SSL Certificate

What are Certificate Authorities & Trust Hierarchies?

Certificate Authorities, or Certificate Authorities / CAs, issue Digital Certificates. Digital Certificates are verifiable small data files that contain identity credentials to help websites, people, and devices represent their authentic online identity (authentic because the CA has verified the identity). CAs play a critical role in how the Internet operates and how transparent, trusted transactions can take place online. CAs issue millions of Digital Certificates each year, and these certificates are used to protect information, encrypt billions of transactions, and enable secure communication.

An SSL Certificate is a popular type of Digital Certificate that binds the ownership details of a web server (and website) to cryptographic keys. These keys are used in the SSL/TLS protocol to activate a secure session between a browser and the web server hosting the SSL Certificate. In order for a browser to trust an SSL Certificate, and establish an SSL/TLS session without security warnings, the SSL Certificate must contain the domain name of website using it, be issued by a trusted CA, and not have expired.

According to analyst site Netcraft (www.netcraft.com), in August 2012 there are almost 2.5m SSL Certificates in use for public facing websites. In reality there are probably as many as 50% more than this number in use that cannot be identified by Netcraft on public facing websites. This makes SSL one of the most prevalent security technologies in use today.