SET in Practice
Purchase by credit card over the Internet involves many functions and actions, of which only a few are implemented in SET. SET provides a payment protocol that defines the communication among cardholder, merchant, and payment gateway for purchases and refunds. It also provides a key exchange protocol, by which the various parties exchange public-key certificates. A number of activities beyond this scope are required. Both cardholders and merchants must obtain certificates that verify their public keys. The process of browsing and selecting goods for purchase is also outside the scope of SET.
On the cardholder side, the cardholder must obtain and install the SET software and arrange a credit card account that supports SET and provides the needed certificate. The merchant must install the merchant-side SET software and integrate this with a web-based product or service ordering system. The merchant's software requirements are more complex, because communication is required both with the cardholder and the payment gateway.
Thus, for SET to work, the supporting software and certification functions must be in place. But, with the backing of the two largest credit-card organizations, Visa and MasterCard, SET is poised to become the standard means for credit card transactions via the Internet.