Chinese Journal of Computers   Full Text
Title	A Fair Multi-Party Non-Repudiation Protocol
Authors	HAN Zhi-Geng LUO Jun-Zhou
Address	(School of Computer Science and Engineering, Southeast University, Nanjing 210096)
Year	2008
Issue	No.10(1705—1715)
Abstract &   Background	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. Keywords multi-party non-repudiation; timeliness; exclusion-freeness; denial of the non-repudiation service attack; replay attack Background The impressive growth of open networks during the last decade has given more importance to several security related problems. The non-repudiation problem is one of them. In comparison to other security issues, non-repudiation has not been studied intensively, meanwhile, most of researches on non-repudiation only toward two-party scenario, and even now, there is still no practical solution for design and verification and deployment of multi-party non-repudiation protocols. Other than two-party non-repudiation protocols, multi-party non-repudiation protocols must respect some special properties. This work is mainly focused on some practical techniques for design and verification and deployment of multi-party non-repudiation protocols. The authors’ early works were focused on design and verification of two-party non-repudiation protocols. With respect to protocol design, they proposed to provide timeliness based on relative time notion, which does not need the support for any global clock synchronism mechanism. And with respect to formal analysis methods, they enhanced SVO logic for time description and made it be able to analyze timeliness of non-repudiation protocols. And based on the techniques used in general security protocols, they also presented a method for modeling and analysis of non-repudiation protocols with Color Petri nets.