A secure server is a web server that uses what’s called a secure socket layer (SSL) for data encryption that allows for private e-commerce transactions. The secure server and SSL encryption protects the private information of an online consumer (name, phone, e-mail, credit card info, etc.).
 
There are companies that provide secure server services to businesses wishing to sell products and services online. Examples of secure server service providers are Verisign and Thawte.
 
IMPORTANT NOTICE: Although Verisign is the leader in both domain name registrations and secure server applications, as of early 2002, they are being sued by GoDaddy.com for deceptive practices, including alleging false and deceptive advertising, interfering with customer relationships, misappropriation of trade secrets, and consumer fraud. If you want to read more about the lawsuit and the circumstances surrounding it, please see their press release.