What is a Single-Root SSL Certificate?
When connecting to a web server over SSL, the visitor’s browser decides whether or not to trust the web site’s SSL certificate based on which Certification Authority (CA) has issued the actual SSL certificate. To determine this, the browser looks at its list of trusted issuing authorities represented by a collection of Trusted Root CA certificates added into the browser by the browser vendor (such as Microsoft or Netscape). Most SSL certificates are issued by CAs who own and use their own Trusted Root CA certificates, such as those issued by GeoTrust and RapidSSL.com. As GeoTrust and RapidSSL.com are known to browser vendors as trusted issuing authorities, their Trusted Root CA certificates has already been added to all popular browsers and, hence are already trusted. These SSL certificates are known as “single-root” SSL certificates. RapidSSL.com, a subsidiary of GeoTrust, owns the Equifax root used to issue its certificates. Some CAs do not have a Trusted Root CA certificate present
