An electronic purchase represents an exchange between money and a digital product or the receipt of a physical product. Atomicity is a desired feature for electronic payment systems because it allows fair purchases. We present a fair payment protocol useful in electronic purchases involving electronic coins. The protocol is fair, asynchronous and efficient, and can be used with existing payment systems. Moreover we have evaluated the role of the TTP in the fair exchange protocol, showing that the incorrect behavior of the TTP can be demonstrated in all cases, so the TTP is verifiable.
['Magdalena Payeras-Capellà', 'Josep Lluís Ferrer-Gomila', 'Llorenç Huguet-Rotger']
Anonymous payment in a fair e-commerce protocol with verifiable TTP