What is a common name?

The common name is the hostname for which an SSL certificate is issued. This can vary between types of certificate. Most commonly, the common name is the entire hostname, such as 'www.yourdomainname.com'. In the case of a wildcard, however, the common name is '*.yourdomainname.com'. For non-web applications of the SSL protocol, such as email certificates, the common name is usually the full email address.