SSL (Secure Sockets Layer) is the standard security technology for establishing an encrypted link between a web server and a browser. SSL is an industry standard and is used by millions of websites in the protection of their online transactions with their customers.
Why have an SSL Certificate?
Any computer in between you and the server can see your credit card numbers, usernames and passwords, and other sensitive information if it is not encrypted with an SSL certificate. When an SSL certificate is used, the information becomes unreadable to everyone except for the server you are sending the information to.