TLS is a cryptographic protocol used to secure data transferred over a network, such as the internet. It is most commonly known for securing web browsing sessions, but it also protects email, VOIP calls, file transfers, and instant messages. It prevents eavesdropping and tampering, which can allow sensitive information like passwords and account numbers to be stolen.
TLS and its predecessor SSL (Secure Sockets Layer) are a part of the TCP/IP stack, allowing them to be used for all types of applications over TCP/IP, not just HTTP. The padlock icon displayed in your browser when a connection is secured by TLS is one of the most familiar examples of how the technology works.
The TLS protocol provides several functions: encryption, authentication, and key exchange. Encryption hides the data transferred between two parties, preventing eavesdropping and tampering. Authentication verifies that the client is communicating with the correct server. Key exchange securely generates and shares a secret session key with the server. This key can then be used to encrypt further communications between the client and the server.
TLS is updated regularly to improve security and performance. For example, TLS 1.3 removes the use of outdated technologies in the handshake and uses newer cipher suites that are more secure. In addition, it reduces the number of round trips required for a full handshake. This saves time and resources. The TLS 1.3 specification is available at the IETF website.
