SSLSecureSocketsLayer) and its successor, TransportLayerSecurity (TLS), are a security protocol that provides security and data integrity for network communication. TLS and SSL encrypt network connections at the transport layer.

SSL was developed by Netscape to ensure the security of data transmission on the Internet. Using data encryption technology can ensure that data will not be intercepted and eavesdropped when transmitting on the network. The general safety standard is 40bit, and the United States has introduced a higher safety standard 128bit, but the export is restricted.

SSL protocol is located between TCP/IP protocol and various application layer protocols, which provides security support for data communication. It is widely used for authentication and encrypted data transmission between Web browser and server.