SSL (Secure Sockets Layer) and TLS (Transport Layer Security) are cryptographic protocols designed to provide secure communication over a computer network, typically between a client (such as a web browser) and a server (such as a web server). They ensure data confidentiality, integrity, and authenticity during transmission, protecting sensitive information from eavesdropping, tampering, or forgery.
SSL, originally developed by Netscape in the mid-1990s, was the predecessor to TLS. It provided a way to establish a secure connection between a client and a server using encryption algorithms and digital certificates. SSL operates at the transport layer of the OSI model, securing data exchanged between applications by encrypting it before transmission and decrypting it upon receipt. SSL versions include SSL 2.0, SSL 3.0, and TLS 1.0, which later evolved into TLS due to security vulnerabilities found in SSL.
TLS (Transport Layer Security) succeeded SSL and is its modern and more secure version. It operates similarly to SSL but includes improvements and stronger cryptographic algorithms to address vulnerabilities found in earlier SSL versions. TLS protocols authenticate communicating parties, encrypt data transmissions to ensure privacy, and use digital certificates to verify the identity of servers and, optionally, clients. TLS is widely used today to secure communications over the Internet, including web browsing, email, instant messaging, and other applications where data privacy and integrity are critical. Major versions of TLS include TLS 1.0, TLS 1.1, TLS 1.2, and TLS 1.3, each introducing enhancements in security, performance, and protocol flexibility over its predecessors.