Research On Group Key Agreement Protocols In Dynamic Peer Group

With the rapid development of network technology and increased Internet-scale, the application areas of dynamic peer group communication (Dynamic Peer Group Communication) is more and more widely, such as video conferencing, network games, real-time information services, distributed simulation, etc. Group key agreement scheme is the cornerstone of the dynamic peer group secure communications, and is the decisive factor of the security group communication systems can become constitute the framework of variety collaborative applications in the open network. However, security and efficiency is often a contradiction in the design of group key agreement protocol, and the formal analysis for the security of a protocol is a very challenging task, so the design of safe and efficient group key agreement scheme is currently a hot spots in the area of international distributed security.Firstly, this paper give a brief analysis of the design of security protocol requirements and the theoretical basis of Group Key Agreement Protocol, present for several typical group key agreement protocol which fit for dynamic peer group, and then analyze Provable Security Theory which cause attention in formal analysis for the security protocol in recent years. The main results are as following:(1) TTS Group Key Agreement Protocol have good computing performance and strong practicality, when analyze on TTS Protocol, we found it can be carried out replay attacks, so proposed two attack program, and then improve the security of TTS Protocol; then use the BCP model of Provable Security theory to formal analyze and prove security of the improved TTS Protocol; finally, we analyze the performance of improved TTS Protocol, analysis show that the security of the Protocol is improved and at the same time the good performance of the Protocol is reserved. The improved TTS Protocol have small calculation overhead, and group key "share" is from the higher level server, so the group key is convenient to be control and management. But with a relatively large number of group members it have large overhead of communication. So it appropriate to the small-scale dynamics peer group which have superior management servers participating in.(2) For large-scale dynamics peer group that did not have higher-level management servers participating in, this paper proposes an Elliptic Curve Cryptography and Triple Tree Based Group Key Agreement Scheme. Firstly, design the initial state of the group key agreement, as well as the way of key update when there are members join or leave, and then use the BCP model formal analyze and prove security of the scheme, and finally we analyze the performance of the proposed scheme, analysis show that the computing and communication overhead is small, so it is efficient.(3) Based on the research of two group key agreement schemes above, we design and realized a prototype system of dynamic peer group communication platform, which the the underlying services is provided by Spread group communication system. First of all, designed the framework of the system and described specific realization method of the main modules, and then achieve an operation and testing of the two schemes accordance to their message structure and work processes, and gives specific analysis of the experimental results.