Analysis of a multi-party fair exchange protocol and formal proof of correctness in the strand space model

Abstract

A multi-party fair exchange protocol is a cryptographic protocol allowing several parties to exchange commodities in such a way that everyone gives an item away if and only if it receives an item in return. In this paper we discuss a multi-party fair exchange protocol originally proposed by Franklin and Tsudik, and subsequently shown to have flaws and fixed by Gonzalez and Markowitch. We identify flaws in the fixed version of the protocol, propose a corrected version, and give a formal proof of correctness in the strand space model. © Springer-Verlag Berlin Heidelberg 2005.