A formal analysis of fairness and non-repudiation in the RSA-CEGD protocol

Abstract

Recently, Nenadić et al. (2004) proposed the RSA-CEGD protocol for certified delivery of e-goods. This is a relatively complex scheme based on verifiable and recoverable encrypted signatures (VRES) to guarantee properties such as strong fairness and non-repudiation, among others. In this paper, we illustrate how an extended logic of beliefs can be helpful to analyze in a formal manner these security properties. This approach requires the previous definition of some novel constructions to deal with evidences exchanged by parties during the protocol execution. The study performed within this framework reveals the lack of non-repudiation in RSA-CEGD and points out some other weaknesses. © Springer-Verlag Berlin Heidelberg 2005.