A Resilient Fair Electronic Contract Signing Protocol

Abstract

Fair exchange between parties can be defined as an instance of exchange such that either all parties involved in the exchange obtain what they expected or neither one does. The authors examine a protocol by Micali that provides fair contract signing, where two parties exchange their commitments over a pre-negotiated contract in a fair manner. They show that Micali’s protocol is not entirely fair and demonstrate the possibilities for one party cheating the other by obtaining the other party’s commitment and not offering theirs. A revised version of this protocol by Bao which provides superior fairness by handling some of the weaknesses is also discussed. However, both these protocols fail to handle the possibilities of a replay attack. Their prior work improves upon these protocols by addressing the weakness that leads to a replay attack. This journal extends their prior work on fair electronic exchange by handling a type of attack which was not handled earlier and provides a brief survey of the recent work related to the field of fair electronic exchange. They also discuss the application of cryptography to our protocol which includes implementation of hybrid cryptography and digital signature algorithms based on elliptic curves to achieve features like confidentiality, data-integrity and non-repudiation.