Secure Sockets Layer (SSL)

Secure Sockets Layer (SSL) is a standard protocol used for the secure transmission of data between a client and server over a network.

SSL uses Transport Control Protocol (TCP) for communication. When using SSL for secure Internet transactions, a Web server needs an SSL certificate to establish a secure SSL connection. SSL encrypts network connection segments above the transport layer, which is a network connection component above the program layer.

SSL is the predecessor of Transport Layer Security (TLS).