Transport layer security (TLS) is a protocol that provides communication security between client/server applications that communicate with each other over the Internet. It enables privacy, integrity and protection for the data that's transmitted between different nodes on the Internet. TLS is a successor to the Secure Sockets Layer (SSL) protocol.
See: RFC2818 - HTTP Over TLS (HTTPS) See: RFC2246 - The TLS Protocol
Source: Transport layer security (TLS)