While the sale of SSL certificates can be profitable as a stand-alone business, SSL certificate sales also help establish customer relationships with e-commerce sites, which typically spend more on web services such as hosting and security. Network Solutions is selling certificates that verify the business details of a certificate applicant, also known as organization-validated certficates. VeriSign and Comodo are the largest players in this segment of the SSL market.

Other authorities, such as GeoTrust and Go Daddy, additionally sell SSL certificates that are validated by confirming that the applicant controls the domain name being secured, known as a domain-validated certificate. Organization-validated certificates account for 75 percent of the SSL certificates in use today, but domain-validated certificates have outsold them in recent months. In April, domain-validated certificates accounted for 57 percent of new sales.

Netcraft’s SSL Survey provides detailed information about encrypted transactions and e-commerce, including the growth rate for SSL-enabled sites, and which operating systems, server software and certificates are most widely used on these sites.