TLS/SSL

Transport Layer Security (TLS) and its predecessor, Secure Socket Layer (SSL), are cryptographic protocols that provide security  for communications over networks such as the Internet. TLS and SSL encrypt the segments of network connections at the Application Layer to ensure secure end-to-end transit at the Transport Layer.

Several versions of the protocols are in widespread use in applications like web browsing, electronic mail, Internet faxing, instant messaging and voice-over-IP (VoIP).

TLS is an IETF standards track protocol, last updated in RFC 5246, that was based on the earlier SSL specifications developed by Netscape Corporation.

get more detail here:
http://en.wikipedia.org/wiki/Transport_Layer_Security