A Novel Contributory Cross-Domain Group Password-Based Authenticated Key Exchange Protocol with Adaptive Security

Adaptively secure group password-based authenticated key exchange (GPAKE) protocols have been proposed intensively during the last decade. These protocols enable group members to establish a secure channel by using low-entropy password to resist against insider attack. However, these protocols cannot be directly applied to establish secure cross-domain group communications, because they are applicable only to the cross-two-domains' group communications. Moreover, quite a few further research studies cross-domain GPAKE (CGPAKE) protocol with contributiveness and explicit authentication. To solve these two problems, we propose a novel CGPAKE protocol with explicit authentication and contributiveness in the universally composable (UC) framework. Compared with existing solutions, our scheme achieves (n/2, n)-contributory, explicit authentication and adaptive security. Meanwhile, the security and performance of communication and computation overloads are also analyzed. To the best of our knowledge, this paper is the first to construct a CGPAKE protocol with adaptive security and contributiveness. Theoretical analysis results show that both security and efficiency of our protocol outperform those existing protocols.