Design and Evaluation of a New Fair Exchange Protocol Based on an Online TTP

Abstract

Security protocols in e-commerce are required to manage the transactions between buyers and sellers. In order to engage customers in e-commerce, these protocols should be well formulated and secured; they should protect both parties from fraudulent users and subsequently promote the growth of e-commerce. There are some protocols, known as fair exchange protocols, in e-commerce that are designed to guarantee fairness between the customer and the merchant so that neither party gains any advantage over the other. Therefore, in this paper, we introduce a new fair exchange protocol for trading products online between a buyer and a seller. The items to be exchanged in this protocol are a digital product and a payment. The following are the characteristics of this new protocol: (1) Dependency on a trusted third party is greatly reduced; further, the protocol also overcomes increased communication overheads and risks, hence leading to substantial improvement in the efficiency and practicality of the protocol. (2) The protocol ensures fairness for all parties and provides an internal dispute resolution mechanism, thereby guaranteeing that none of the parties involved in the transaction suffer unfairly in case one of the entities disappears before the transaction is formalized. (3) The protocol consists of three messages exchanged between the buyer (customer) and the seller (merchant).