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CBACS: A Privacy-Preserving and Efficient Cache-Based Access Control Scheme for Software Defined Vehicular Networks

In vehicular networks, caching content in fog nodes is a widely accepted and favorable way to quickly respond to massive vehicle requests, reduce content retrieval delay and improve service quality. However, to implement such caching mode, it is critical to ensure efficient security and privacy protection when vehicles access the cached content in fog nodes. In this paper, aiming at the security issue, a novel lightweight cryptography-based access control scheme for software defined vehicular networks (SDVN) is proposed, by using TESLA broadcast authentication protocol and Pederson commitment. The scheme realizes direct and efficient authentication between vehicles and fog nodes while limiting only legitimate vehicles can get request responses, and avoids limitations or deficiencies in existing access control schemes. Moreover, considering the limited cache space of the fog node, by utilizing the flexibility of the SDN paradigm, a cooperative cache update mechanism is provided. The security verification with ProVerif and detailed security analyses prove that the scheme can meet the security requirements in SDVN. And compared with the related works, our scheme achieves better performance in terms of computation and communication costs.