Revocable and Conditionally Anonymous Certificateless Authentication for VANETs

Abstract

Vehicular Ad-hoc Networks (VANETs) serve as the cornerstone of Intelligent Transportation Systems (ITS), facilitating real-time communication between vehicles and infrastructure to enhance road safety and traffic efficiency. However, authentication schemes in VANETs still face several issues, such as high computational overhead, neglect of conditional privacy, lack of revocation mechanisms, and disregard for physical security. To address these challenges, we propose a Revocable and Conditionally Anonymous Certificateless Authentication Scheme with Anti-Physical Theft Protection. First, this scheme employs a pairing-free certificateless aggregate signature to significantly improve computational efficiency. Second, we design a conditional anonymity mechanism that dynamically assigns pseudonyms to conceal a vehicle’s real identity while allowing a trusted authority (TA) to recover the true identity when necessary. Moreover, this scheme adopts a Dynamic Sparse Merkle Tree (DSMT) to achieve efficient pseudonym revocation, enabling real-time identity management without incurring excessive communication overhead. Meanwhile, recognizing the threat of physical attacks, the scheme enhances security by integrating Physical Unclonable Functions (PUFs) and fuzzy extractors, which bind cryptographic keys to unique hardware characteristics to resist physical extraction attacks. Finally, rigorous security analysis and performance evaluations confirm that the proposed scheme outperforms existing approaches in both reliability and efficiency.