A protocol for fair electronic purchase based on concurrent signatures

Abstract

E-commerce protocols for the electronic purchase of goods are difficult to design and implement due to their complexity and high security demands. Fairness of such protocols in literature highly depends on an additional TTP(trusted third party). However, it is difficult to find such a TTP in some situations. In addition, fairness for customers has been neither fully considered nor well satisfied in existing electronic purchasing protocols. In this paper, a new protocol FEP (fair electronic purchase) without a special TTP but an online bank is presented based on a concurrent digital signature scheme. The FEP protocol guarantees fair electronic purchase of goods via electronic payment between consumers, merchants and their online banks. The protocol is practical and the analysis based on the game logics shows that it achieves the properties of viability, fairness, and timeliness.