Secure Sockets Layer (SSL): How It Works

A browser attempts to connect to a Web site secured with SSL.

Web servers and Web browsers rely on the Secure Sockets Layer (SSL) protocol to create a uniquely encrypted channel for private communications over the public Internet. Each SSL Certificate consists of a public key and a private key. The public key is used to encrypt information and the private key is used to decipher it. When a Web browser points to a secured domain, a level of encryption is established based on the type of SSL Certificate as well as the client Web browser, operating system and host server capabilities. That is why SSL Certificates feature a range of encryption levels such as "up to 256-bit".

Strong encryption, at 128 bits, can calculate 2⁸⁸ times as many combinations as 40-bit encryption. That’s over a trillion times stronger. At current computing speeds, a hacker with the time, tools and motivation to attack using brute force would require a trillion years to break into a session protected by an SGC-enabled certificate. To enable strong encryption for most site visitors, choose an SSL Certificate that enables at least 128-bit encryption for 99.9% of Web site visitors. True 128-bit SSL Certificates

Credentials for establishing identity are common: a driving licence, a passport, a company badge. SSL Certificates are credentials for the online world, uniquely issued to a specific domain and Web server and authenticated by the SSL Certificate provider. When a browser connects to a server, the server sends the identification information to the browser. To view Web site credentials:

• Click the closed padlock in a browser window
• Click the trust mark (such as the VeriSign Trust™ Seal)
• Look in the green address bar*

*Only SSL Certificates with EV trigger high-security Web browsers to display your organisation name in a green address bar. (Learn more about SSL Security and Extended Validation).

Trust of a credential depends on confidence in the credential issuer, because the issuer vouches for the credential's authenticity. Certificate Authorities use a variety of authentication methods to verify information provided by organisations. VeriSign, the leading Certificate Authority, is well known and trusted by browser vendors because of our rigorous authentication methods and highly reliable infrastructure. Browsers extend that trust to SSL Certificates issued by VeriSign.

New features available with all VeriSign® SSL Certificates do more than secure transactions and establish trust online. The new VeriSign Trust™ Seal, VeriSign Seal-in-Search™ technology, and daily Web site malware scanning work together with your premium SSL Certificate to help assure your customers that your site is safe from search to browse to buy.