CRT-AS: A Chinese Remainder Theorem-Based Authentication and Key Agreement Scheme for SDVN

Traditional Authentication Key Agreement (AKA) schemes in Vehicular Ad-hoc Networks (VANETs) face high computational and communication overheads, as well as reliance on a single Trust Authority (TA), creating bottlenecks and single points of failure. To address these issues, we propose a lightweight and privacy-preserving AKA scheme for Software Defined Vehicular Network (SDVN) based on the Chinese Remainder Theorem (CRT). The scheme uses a multi-controller model in Software Defined Network (SDN), where the root TA is responsible only for vehicle registration, while regional SDN controllers manage edge node registration. During authentication, session keys are generated and distributed using CRT without the need for the root TA's online participation, reducing overhead. Additionally, vehicles can independently generate dynamic anonymity, eliminating the need for anonymity update requests to the TA or pre-storing large amounts of anonymity data. The overhead analysis shows that the proposed scheme outperforms comparison schemes in communication and computational overhead. Simulation results indicate that it achieves lower packet loss rates and transmission delays compared to baseline schemes.