Secure sockets layers (SSL) is a cryptographic protocol designed to secure communications over a computer network. SSL establishes an encrypted link between a web server and a browser, ensuring that all data transmitted between them remains private and integral. It involves a handshake process to authenticate the server (and, optionally, the client) and negotiate encryption keys. SSL is used to protect sensitive information such as login credentials, credit card details, and personal data from being intercepted or tampered with by unauthorized parties. Although SSL has been largely succeeded by TLS (Transport Layer Security), it remains a foundational technology in the evolution of secure online communication.