Further observations on optimistic fair exchange protocols in the multi-user setting

Authors

Xinyi Huang, Singapore Management UniversityFollow
Yi Mu, University of WollongongFollow
Willy Susilo, University of WollongongFollow
Wei Wu, University of WollongongFollow
Yang Xiang, Deakin UniversityFollow

RIS ID

35748

Publication Details

Huang, X., Mu, Y., Susilo, W., Wu, W. & Xiang, Y. (2010). Further observations on optimistic fair exchange protocols in the multi-user setting. In P. Nguyen & D. Pointcheval (Eds.), 13th International Conference on Practice and Theory in Public Key Cryptography (PKC 2010) (pp. 124-141). Germany: Springer.

Abstract

Recent research has shown that the single-user security of optimistic fair exchange cannot guarantee the multi-user security. This paper investigates the conditions under which the security of optimistic fair exchange in the single-user setting is preserved in the multi-user setting. We first introduce and define a property called “Strong Resolution-Ambiguity”. Then we prove that in the certified-key model, an optimistic fair exchange protocol is secure in the multi-user setting if it is secure in the single-user setting and has the property of strong resolution-ambiguity. Finally we provide a new construction of optimistic fair exchange with strong resolution-ambiguity. The new protocol is setup-free, stand-alone and multi-user secure without random oracles.