1. How to implement SSL or TLS secure communications
http://www.zdnet.com/blog/ou/how-to-implement-ssl-or-tls-secure-communications/608
2. HTTP Secure (HTTPS)
http://en.wikipedia.org/wiki/HTTP_Secure
3. Session Initiation Protocol (SIP)
http://en.wikipedia.org/wiki/Session_Initiation_Protocol
4. SSL
http://en.wikipedia.org/wiki/SSL
5. TLS