Description: Secure Socket Layer (SSL), is a mature technology based on server/client architecture that is adopted by majority of websites and internet service providers as a defense agaist various online security compromises. In most implementations, it is server authenticated and client to server secured. It is easy to use but has limitations. For example, it can't prevent a person who knows another person's credit card number (not necessarily by intercepting and decoding the SSL communication data, which is quite hard indeed) from using the card (details).

Description: PayPal is a third party payment gateway that provide user accounts for their financial transactions on the internent. It is protected using SSL technology (details).