SSL certificates provide security for a website's end user by verifying the server's owner and encrypting data to and from the site. There are two online tools that can help you verify your certificate signing request and cert installation as well as scan your SSL server for vulnerabilities.
UNL, through it's association with InCommon, provides SSL certs free of charge to the campus by paying a flat fee annually.
For details, go to http://security.unl.edu/sslcerts