This is a brief overview intended for the typical Internet user. For a more in-depth, technical look at SSL, watch out for the appropriate article in The Minstrel's Papers on Privacysense.

SSL stands for Secure Socket Layer, created by Netscape for the purpose of allowing secure communication between servers and browsers.

SSL allows for secure communication, but it cannot ensure that you have not accidentally accessed a site posing as the one you wanted. If you bank online, the institution has probably warned you to be careful to ensure that it is the real bank website you are logging into, and not one that simply appears to be the same. This is the sort of problem many websites are facing.

The most effective response has come in the form of the SSL certificate. Put simply, a valid certificate confirms that the website owner is who s/he claims to be, i.e. s/he owns the website and can be identified in the real world.

You can come across SSL certificates being used in a number of ways, but the easiest one to spot is when you go to an e-commerce site where the trader has signed up for a server certificate, complete with logo. This is obtained from a company such as Verisign or Thawte (which is owned by Verisign) and to get one, the trader must provide certain information and sign a declaration in the presence of a legal professional (e.g. a solicitor). Although the trader displays a logo on the shop website, do not accept this as proof of everything, but merely an invitation to check - you must click on it in order to gain the useful information: the name of the company and domain name (the website address) should match, and the certificate should not have expired. If the certificate has expired, or the information doesn't match, think twice before proceeding with anything on the site that involves parting with personal data, such as your real world contact details or credit card information.

For an example of what a certificate might look like, see mine at the World of Sense Shop (scroll down and click on the Thawte 'Secure Site' icon).