Research On Group Key Agreement Protocols For Mobile Environment

Nowadays,wireless mobile communication has been used in every aspect of our lives.Currently,it is not only limited to telecommunications,but also has entered the entertainment,security,business and other fields.A mobile environment refers to an unbalanced network composed of several mobile nodes with limited computing power and powerful nodes with limited resources.Now there are many group-oriented applications based on the mobile environment,such as video conferences on mobile phones,office work on mobile devices and so on.With the increasing popularity of grouporiented applications,how to ensure the security of group communication and avoid privacy leakage in the mobile environment has become an important problem that needs to be solved urgently.Then,group key agreement is an obvious choice.In view of the fact that the traditional group key agreement protocol is not suitable for networks with different computing capabilities of participating nodes,and the current protocol has the problems of poor contribution of confirmed members,difficult to provide dynamic membership,difficult to guarantee forward and backward secrecy,high communication cost and the high computational cost,thesis designs two dynamic group key agreement protocols suitable for mobile environments.The main contributions of the thesis are as follows:(1)A dynamic group key agreement protocol suitable for mobile environments is proposed.The protocol adopts the method of non-bilinear pairing,and on the basis of optimizing the joining efficiency,the function of confirming the contribution value of members to the session key is added.Thesis first introduces the protocol structure and security model of the protocol,and then analyzes the security of the protocol through formal proof and informal analysis.Finally,from the perspective of calculation cost,it is found that after running 5 rounds of joining phase based on the 80-bit security level,the calculation time of the central node does not change greatly due to the increase of the number of members,and the time is reduced by 264.79 ms compared with the protocol of Mandal et al.The joining efficiency increased by 76.2%.(2)An asymmetric group key agreement protocol suitable for mobile environment is proposed.The protocol adopts the non-bilinear pairing method to improve the overall calculation efficiency of the protocol and has the function of members' confirmation of the contribution value of the session key.Thesis first introduces the protocol construction and security model of the protocol,and then analyzes the security of the protocol through formal proof and informal analysis.Finally,from the perspective of computational cost,compared with the protocol of Mandal et al.,under the same 80-bit security level,the running time of the proposed protocol is reduced by 53.26 ms,which is a significant improvement.