Secure Sockets Layer (SSL)

Secure Sockets Layer (SSL) was a widely used cryptographic protocol for providing data security for Internet communications. SSL was superseded by TLS; however, most people still refer to Internet cryptographic protocols as SSL.

Both SSL and TLS a layer of security on top of a Network Protocol.

There were three main versions of this protocol:

• SSL 1.0
• SSL 2.0
• SSL 3.0

SSL 1.0 was known to be insecure, and therefore never published.

SSL 2.0 was in use from 1995. It used the rather weak MD5 Hashing algorithm and was vulnerable to a number of attack vectors, among which Man in the Middle, that led to its decommissioning in 2011.

SSL 3.0 was a complete redesign of SSL. In 2014 it was found to be vulnerable to the POODLE attack, which affected all block ciphers, and so it was deprecated in 2015, when it was replaced by TLS.