A Secure and Low-Overhead Authentication Protocol for Vehicle Ad Hoc Networks with Batch and Transfer Authentication

Vehicular Ad Hoc Networks (VANETs) require secure, efficient, and scalable authentication mechanisms to ensure trust among vehicles and roadside units (RSUs). Traditional one-to-one authentication approaches often lead to high communication and computational overheads, making them unsuitable for large-scale vehicular environments. This leads to a security traffic jam, rendering the process inefficient and unsuitable for real-time safety applications. To address this, study proposes a lightweight authentication protocol that supports both batch and transfer authentication, enabling multiple vehicles to be authenticated simultaneously and allowing authentication validity to be transferred between RSUs without re-executing the full protocol. In batch authentication, a roadside unit verifies a group of vehicles simultaneously instead of one at a time, much like a guard approving an entire busload of pre-verified passengers, which greatly reduces delays at intersections or toll booths. In transfer authentication, when a vehicle moves from one roadside unit's area to another, the verification data are securely transferred, allowing seamless continuity without restarting the process, similar to a concert wristband that lets attendees move between stages without repeated checks. This scheme leverages the mathematical properties of Chebyshev polynomials to provide strong security with reduced overhead. Performance analysis shows that the proposed method achieves a communication cost of only 42n bytes and a significantly lower computational complexity than existing schemes. This approach enhances scalability, reduces message exchange, and maintains robust resistance against common attacks, making it well-suited for real-time vehicular communications. Overall, this new protocol enhances the practicality of VANETs by reducing data overhead, accelerating authentication, and efficiently managing high traffic volumes, making it a secure and scalable solution for the future of intelligent transportation systems.