Transport Layer Security (TLS), the successor of the now deprecated Secure Sockets Layer (SSL). It is a cryptographic protocol designed to provide communications security over a computer network. Several versions of the protocols are widely used in applications such as email, instant messaging, and voice over IP, but its use as the Security layer in HTTPS remains the most publicly visible.

The TLS protocol aims primarily to provide privacy and data integrity between two or more communicating computer applications. The TLS protocol comprises two layers: the TLS record and the TLS handshake protocols.