LAKAS-N: Quantum Attack-Resistant Lattice-Based Authentication and Key Agreement using NIZK for Single and Cross-Domain VANETs

Abstract

Authenticated key exchange and secure handover between vehicles and roadside units (RSUs) are essential for the reliability of vehicular networks. However, many existing approaches incur high computational and communication overhead or rely on re-authentication, which limits scalability under high mobility. Moreover, conventional schemes based on classical cryptography cannot withstand quantum adversaries, while lattice-based solutions overlook the need for efficient handover and strong privacy protection. To address these limitations, a lattice-based authentication and key agreement protocol that integrates non-interactive zero-knowledge (NIZK) proofs to enable seamless and post-quantum secure handover in both intra-domain and cross-domain vehicular networks (LAKAS-N) is proposed in this work. The scheme establishes mutual key exchange between vehicles and RSUs, eliminates re-authentication within a single domain, and preserves anonymity when transitioning across domains. Security is rigorously validated through informal and formal analyses, including Scyther-based verification, which confirms resistance against classical and quantum attacks. Lastly, a comprehensive evaluation shows that LAKAS-N achieves stronger security with substantially lower computational, communication, storage, and energy costs compared to state-of-the-art protocols, demonstrating its practicality for real-world vehicular networks.