First of all, what does SSL stand for?
SSL stands for ‘Secure Sockets Layer’.
Secure Sockets Layer (SSL) is “standard security technology that establishes an encrypted link between a web server and a browser. It makes sure that all data passed between the web server and browser remain private and integral. The complexities of the SSL protocol remain invisible to you, the customer/visitor. Instead, your browser provides you with a key indicator to let you know you are currently protected by an SSL encrypted session.
For more information about Secure Sockets Layer (SSL), visit the link below.
Quoted from: http://info.ssl.com/article.aspx?id=10241