A Fair Multi-Party Non-Repudiation Protocol

Abstract

Practical multi-party non-repudiation protocols must respect viability,fairness,timeliness,exclusion-freeness and confidentiality.In this paper,the authors point out that most of the existing representative multi-party non-repudiation protocols with online trusted third party,such as KM and its extensional version OZCL and OZL,lack the supports for the properties of timeliness and exclusion-freeness,and are vulnerable to denial of the non-repudiation service attack and so on.Bearing these issues in mind,the authors present a new protocol NKM,which respects timeliness with time-span notion,which does not need any global clock synchronism mechanism,and respects exclusion-freeness and confidentiality with double group encryption notion,and makes evidence managed efficiently and avoids potential denial of non-repudiation service attack and replay attack with evidence chain notion.Subsequently,the authors give a formal analysis of its security and put some consideration on some security issues of protocol deployment.Compared with existing protocols,NKM have advantage over them in terms of security and performance and can be a practical protocol.