Physically Secure Lightweight and Privacy-Preserving Message Authentication Protocol for VANET in Smart City

Secure message transmission in vehicular communications in smart cities is still a challenging task. Most of the related work employed the Public Key Infrastructure, Certification Revocation Lists (CRLs) for ensuring security, privacy. However, these work suffered from some issues such as: 1) the time-consuming checking process, huge size of CRLs, 2) traceability attacks by linking unencrypted Basic Safety Messages (BSMs), 3) extracting secret keys from the storage of parked vehicles or road-side units (RSU) by an adversary. To address the aforementioned issues, we thus propose a physically secure privacy-preserving message authentication protocol using Physical Unclonable Function (PUF), Secret Sharing. The proposed protocol guarantees security, privacy against passive, active attacks even under memory leakage. The entities (i. e. , vehicles, RSU) make use of their PUF to reconstruct a secret polynomial-share so that pairwise temporal secret keys (PTKs) can be established with other entities. Unlike existing protocols, BSMs are also encrypted in our protocol (by PTKs) to provide a higher level of security, thwart vehicles traceability attacks. To revoke a vehicle, RSU needs not broadcast CRLs. Instead, RSU distributes only a secure offset key using threshold Secret Sharing. Consequently, our revocation checking process has computation complexity O (1). Our protocol also eliminates the need for a third party in Vehicle-to-Vehicle communication to ensure expeditious transmission. Security analysis, performance evaluation show that our proposed protocol outperforms existing schemes in terms of security features, computation, communication cost.