Secure Socket Layer Secure socket layer checks digital certificate that authenticates connection of web server. SSL (Secure Sockets Layer) and its successor, [[Protocols/TLS]] (Transport Layer Security), are protocols for establishing authenticated and encrypted links between networked computers. Although the SSL protocol was deprecated with the release of TLS 1.0 in 1999, it is still common to refer to these related technologies as “SSL” or “SSL/TLS.” The most current version is TLS 1.3, defined in RFC 8446 (August 2018).