What is Transport Layer Security (TLS)?
Transport Layer Security (TLS) is an internet security protocol for encrypting data sent over the internet. Sites secured with transport layer security begin with https://, unlike unsecured sites, which start with http://.
A transport layer security connection begins with a handshake. That is, the web client and server agree on the algorithm and secret key to be used for that session. That way, they can ensure that the transmitted data is private and cannot be intercepted by unauthorized parties.
TLS is the successor to Secure Sockets Layer (SSL). The secure sockets layer itself is obsolete and hasn’t been updated since SSL 3.0 was released in 1996. However, many internet users still use the term, secure sockets layer, when referring to transport layer security.