摘要：Aimed at the problem of the fairness analysis for multiparty nonrepudiation protocols, a new formal analysis method based on improved strand space is presented. Based on the strand space theory, signature operation is added; the set of terms, the subterm relation and the set of penetrator traces are redefined and the assumption of free encryption is extended in the new method. The formal definition of fairness in multi-party non-repudiation protocols is given and the guideline to verify it based on improved strand space is presented. Finally, the fairness of multi-party non-repudiation protocols is verified with an example of Kremer-Markowitch protocol, which indicates that the new method is suitable for analyzing the fairness of multiparty nonrepudiation protocols.
