Transport Layer Security (TLS)
A slightly modified version of Secure Sockets Layer SSL version 3, called Transport Layer Security (TLS), has been standardized by the IETF (Internet Engineering Task Force ) [RFC 2246]. TLS uses HMAC for MAC, additional alert codes, different digest functions and different set of encryption algorithm.
A simplified version of SSL, one that will allow us to get a big-picture understanding of the why and how of SSL. We will refer to this simplified version of SSL as “almost-SSL.”
Almost-SSL (and SSL) has three phases: handshake, key derivation, and data transfer.