Research On Constant-Round Group Key Agreement Protocol And Its Applications

The group key agreement protocol is a cryptographic primitive which is used to achieve secure group communication.Such protocols allow a group of users to negotiate a shared one-time session key and use this key to secure the group communication in an open network.All users must keep online at the same time during the execution of the protocol.The number of communication rounds,i.e.,the number of interactions and online duration required for the users to execute the key agreement protocol,is one of the important benchmarks to evaluate the online time of the involved users.The constantround group key agreement protocol is classified as a group key agreement protocol with a fixed number of communication rounds(regardless of the number of group members).Since such protocol can significantly reduce the user's online collaboration time while ensuring the security,it has broad application prospects and has become the research hotspot in the field of information security.In this thesis,the constant-round group key agreement protocol and its application are studied in detail,and the contributions in the thesis are listed as follows:1.First of all,this thesis summarizes the-state-of-the-art of the constant-round group key agreement protocols,including the existing formal definitions,security models,design goals and the evaluation criteria,the design philosophies and construction method of the classical scheme.2.Secondly,this thesis studies the construction of the constant-round group key agreement protocol supporting dynamic group operations.By combining the elliptic curve cryptosystem and the certificateless cryptosystem,this thesis presents an authenticated constant-round group key agreement protocol which supporting dynamic group operations and proves the security of the scheme under the random oracle model.Subsequently,this thesis uses the simulation experiments to analyze the communication overhead and computation overhead of the proposed protocol.The analysis shows that the protocol is more efficient than the-state-of-the-art.According to the existed assessment criteria,this protocol meets all security requirements.3.Finally,this thesis studies the construction of group key agreement protocol applicable to the vehicle ad hoc network.Through the analysis of this application scenario,the design goal of the group key agreement protocol for vehicle ad hoc networks is described.By combining the quadratic residue cryptosystem and the identity-based public key cryptosystem,this thesis proposed an efficient and provable security constant-round anonymous group key agreement protocol and proves the security of the scheme under the random oracle model.Subsequently,this thesis analyzes the security and efficiency of the scheme.The analysis shows this protocol meets all requirements compared to the-state-of-the-art.