The Secure Socket Layer (SSL) and Transport Layer Security (TLS) is the most widely deployed security protocol used today. It is essentially a protocol that provides a secure channel between two machines operating over the Internet or an internal network. In today’s Internet focused world, the SSL protocol is typically used when a web browser needs to securely connect to a web server over the inherently insecure Internet.
Technically, SSL is a transparent protocol which requires little interaction from the end user when establishing a secure session. In the case of a browser for instance, users are alerted to the presence of SSL when the browser displays a padlock, or, in the case of Extended Validation SSL, when the address bar displays both a padlock and a green bar. This is the key to the success of SSL – it is an incredibly simple experience for end users.