Efficient and Security-Enhanced Certificateless Aggregate Signature-Based Authentication Scheme With Conditional Privacy Preservation for VANETs

Vehicular ad-hoc networks (VANETs) are integral to the evolution of intelligent transportation systems, offering substantial benefits in managing traffic flow, issuing warnings for potential accidents, and delivering information services to drivers. To ensure the authenticity and integrity of data exchanged within VANETs, numerous authentication schemes based on certificateless aggregate signature (CLAS) have been developed. However, state-of-the-art solutions often fail to be applicable in real-world VANETs due to security weaknesses and operational inefficiencies. Recently, Zhu et al. proposed an efficient CLAS-based authentication scheme with conditional privacy preservation (CPP) for VANETs (IEEE Transactions on Intelligent Transportation Systems, DOI: 10.1109/TITS.2023.3275077). Unfortunately, our analysis reveals that Zhu et al.'s scheme is incapable of withstanding coalition attacks from malicious RSUs and vehicles as well as public-key replacement attacks from dishonest vehicles. To facilitate secure communication in VANETs, we present a security-enhanced, pairing-free and energy-efficient CLAS-based authentication scheme with CPP for VANETs. This scheme has been rigorously proven to be secure against Type I, Type II and Type III attackers. Distinguished from other comparable schemes, our construction significantly reduces communication overhead and energy consumption while simultaneously fortifying security.