What is SSL? SSL is an abbreviation standing for 'Secure Sockets Layer'. This is a protocol developed by Netscape for transmitting private documents via the Internet. SSL works by using a private key to encrypt data that is to be transmitted over the SSL connection. Both Netscape Navigator and Internet Explorer support SSL, and many Web sites use the protocol to obtain confidential user information, such as credit card numbers. By convention, URLs that require an SSL connection start with https:// instead of http://. [ Close Window ]