A Post-Quantum Certificateless Aggregate Signature Scheme for VANETs Resilient to Rogue-Key Attacks

—Vehicular Ad Hoc Networks (VANETs) requires lightweight and scalable authentication mechanisms to ensure that high-speed mobile nodes can successfully communicate with each other in a safe and reliable manner. Classic Certificateless Aggregate Signature (CLAS) cannot solve quantum-era problems and easily allows for key forgeries since they rely on classical cryptographic assumptions as the Elliptic Curve Discrete Logarithm Problem (ECDLP). This paper presents a Post-Quantum Certificateless Aggregate Signature (PQ-CLAS) scheme to provide a quantum-resistant level of security and add robust protection against rogue keys and even a maliciously operated Key Generation Center (KGC) attack. Security analysis shows that the proposed scheme combines double verification with lightweight computation. The results are impervious to impersonation attacks, replay attacks, and man-in-the-middle attacks. Experimental figures show that the average signature time for PQ-CLAS is 1.25 ms, verification time is 2.85 ms. By contrast with aggregate verification of 100 vehicles taking 302 ms and with a communication overhead per message of 1440 bits, the results are approximately 18% better than recent existing work (2022). This demonstrates that PQ-CLAS can provide an efficient, scalable, and quantum-resistant hardware