SSL
From Innopaydia
Secure Socket Layer. A method designed to ensure the safe exchange of Internet data between a website and your browser. The data are encrypted to ensure that nobody else can see or track them, for instance credit card data. As soon as you open a website with SSL, you are alerted by your browser, and a small key or padlock (depending on the type of browser you use) is visible as long as the security is operational. By clicking on the key or padlock you can check the authenticity of the provider.