SSL stands for Secure Sockets Layer and was originally created by Netscape. It is used for providing confidentiality, authenticity and integrity by establishing an encrypted link between a server and a client. This link ensures that all data passed between the web server and browsers remain private and integral. SSLv2 and SSLv3 are the 2 versions of this protocol (SSLv1 was never publicly released). After SSLv3, SSL was renamed to TLS. Those protocols are standardized and described by RFCs.