An Enhanced and Lightweight Anonymous Authentication Protocol Based on PUF for VANETs

With the rapid advancement of mobile communication technologies, privacy preservation in VANETs has emerged as a pivotal research frontier. Previous authentication protocols often face challenges such as key leakage risks and high computational overhead. Physical Unclonable Functions (PUFs), as a lightweight hardware primitive, offer a promising solution for enhancing security in VANETs. Recently, Xie et al. designed an anonymous authentication protocol for VANETs. Unfortunately, our analysis reveals that their protocol cannot resist ephemeral key leakage attacks. To address these limitations, we propose an enhanced PUF-based anonymous authentication protocol, referred to as iXDZ. Our protocol leverages PUF challenge-response mechanisms to generate real-time vehicle keys, eliminating the need to store long-term keys on vehicles and thereby preventing physical key extraction attacks. Our protocol not only resists ephemeral key leakage attacks but also utilizes the uniqueness, unpredictability, and tamper-resistance of PUF to defend against RSU capture attacks and various physical attacks, meeting the diverse security requirements of VANETs. Furthermore, it is anonymous and lightweight, protecting user privacy and enhancing overall network trust. We rigorously demonstrate the security of iXDZ under the random oracle model and supplement the proof utilizing the Scyther formal analysis tool. Performance evaluations reveal that iXDZ significantly enhances security while reducing computational and communication overhead. Additionally, a case study highlights that iXDZ achieves a 33.3% reduction in execution time compared to the original protocol.