What is SSL

The Secure Sockets Layer (SSL) protocol, originally developed by Netscape, has become the universal standard on the Web for authenticating Web sites to Web browser users, and for encrypting communications between browser users and Web servers. Because SSL is built into all major browsers and web servers, simply installing a digital certificate, or SSL Certificate, enables SSL capabilities. 

What is a SSL Certificate?

Installed on your Web server, a SSL Certificate is a digital credential that enables visitors using Web browsers to verify your site's authenticity and to communicate with it securely via SSL encryption.

What are authentication and encryption?

SSL server authentication allows users to confirm a Web server's identity. SSL-enabled client software, such as a Web browser, can automatically check that a server's certificate and public ID are valid and have been issued by a certificate authority (CA) - such as VeriSign - listed in the client software's list of trusted CAs. SSL server authentication is vital for secure e-commerce transactions in which users, for example, are sending credit card numbers over the Web and first want to verify the receiving server's identity.

An encrypted SSL connection requires all information sent between a client and a server to be encrypted by the sending software and decrypted by the receiving software, protecting private information from interception over the Internet. In addition, all data sent over an encrypted SSL connection is protected with a mechanism for detecting tampering - that is, for automatically determining whether the data has been altered in transit. This means that users can confidently send private data, such as credit card numbers, to a Web site, trusting that SSL keeps it private and confidential.

How do SSL Certificates work?

A customer contacts your site and accesses a secured URL: a page secured by a SSL Certificate (indicated by a URL that begins with "https:" instead of just "http:" or by a message from the browser). 

Your server responds, automatically sending the customer your site's digital certificate, which authenticates your site. 

Your customer's Web browser generates a unique "session key" to encrypt all communications with the site. 

The user's browser encrypts the session key itself with the site's public key so only the site can read the session key. 

A secure session is now established. It all takes only seconds and requires no action by the user. Depending on the browser, the user may see a key icon becoming whole or a padlock closing, indicating that the session is secure. 

What is the difference between a 40-bit SSL (Secure Server) ID and a 128-bit SSL (Global Server) ID?

SSL comes in two strengths, 40-bit and 128-bit, which refer to the length of the "session key" generated by every encrypted transaction. The longer the key, the more difficult it is to break the encryption code. 128-bit SSL encryption is the world's strongest: according to RSA Labs, it would take a trillion-trillion years to crack using today's technology.