HCPA-GKA: A hash function-based conditional privacy-preserving authentication and group-key agreement scheme for VANETs

In recent years, the continuous economic development and the emergence of new technologies have made vehicles an indispensable travel tool in people's lives. However, the intelligent and efficient control and management of the increasing number of vehicles to improve traffic efficiency has become a problem. Vehicular ad hoc networks (VANETs) are one of the most important development trends that are used for communication between vehicles to provide information such as weather conditions, road conditions, and traffic jams and their status, which is significant in improving traffic safety and efficiency. In this scenario, authenticating the entity that is sending the message is a critical task to ensure secure communication in VANETs. In this paper, we propose a conditional privacy-preserving authentication scheme based on the hash function, which does not use complex bilinear mapping and elliptic curve encryption for identity authentication to prevent illegal vehicle interference and ensure the legitimacy of the source. Meanwhile, a group key agreement mechanism based on the Chinese remainder theorem (CRT) is proposed to distribute the group key for authenticated vehicles. The group key can be updated when the vehicle joins and leaves the group. In the process of anonymous message generation and verification, analysis of the results shows that our proposed scheme satisfies the security privacy requirements and has significant advantages in terms of computation cost and communication overhead compared with existing schemes.