Secure Sockets Layer (SSL) is a protocol for enabling data encryption on the intranet and for helping web site users confirm the owner of the web site. SSL is most commonly used to protect communications between web browsers and servers. However it is increasingly used for server to server communications and for web-based applications.
What Is SSL?
You can view SSL information by clicking the padlock icon at the beginning of the address bar on your browser when at the PayPal checkout.