A new authentication scheme for dynamic charging system of electric vehicles in fog environment

The dynamic charging system of electric vehicles has great potential for development. Electric vehicles initiate charging requests, and charging stations charge authorized electric vehicles. Fog computing improves the efficiency of request processing. However, open channels can be vulnerable to various attacks by a malicious adversary. Mutual authentication schemes allow users and charging stations to confirm each other. Therefore, numerous authentication and key agreement schemes have been proposed. In 2021, Babu et al. proposed an authentication scheme based on fog servers. Unfortunately, we found that their scheme can not resist FS impersonation attack and replay attack. Hence, we propose an authentication scheme between electric vehicles and fog servers to resolve the security weakness. Our scheme uses lightweight hash functions and XOR operations, which is more suitable for resource‐constrained electric vehicles. We proved our scheme can achieve mutual authentication by using BAN logic, and analyzed that our scheme can resist impersonation, replay, and known session key attacks, ensuring anonymity and untraceability. We finally compare computation cost and communication cost of our scheme with the existing schemes. The result shows that our scheme performs better than others overall. Therefore, our scheme is secure and suitable for dynamic charging systems.