Fair Electronic Exchange Based on Fingerprint Biometrics

Abstract

Fair exchange between two parties can be defined as an instance of exchange such that either both parties obtain what they expected or neither one does. Protocols that facilitate such transactions are known as “fair exchange protocols”. We analyze one such protocol by Micali that demonstrates fair contract signing, where two parties exchange their commitments over an already negotiated contract. In this journal we show that Micali’s protocol is not completely fair and demonstrate the possibilities for one party cheating by obtaining the other party’s commitment and not offer theirs. A revised version of this protocol by Bao provides superior fairness by handling the above mentioned weakness but fails to handle the possibility of a replay attack. Our proposed protocol improves upon Bao’s protocol by addressing the weakness that leads to a replay attack. We also demonstrate a software implementation of our system which provides fair contract signing along with properties like user authentication achieved through the use of a fingerprint based authentication system and features like confidentiality, data-integrity and non-repudiation through implementation of hybrid cryptography and digital signatures algorithms based on Elliptic Curve Cryptography.