A Quantum-Resistant Authentication and Key Agreement Protocol for Fog-Assisted Vehicular Networks

Abstract

Fog-based Vehicular Ad Hoc Networks (VANETs) support low-latency services by providing computing resources in close proximity to vehicles, but they also face security threats arising from Fog Node (FN) compromise and advances in quantum computing. In this paper, we analyze a recently proposed elliptic curve cryptography (ECC)-based authentication and key agreement (AKA) protocol and show that exposure of the FN’s secret information can lead to FN impersonation and session key compromise. In addition, the existing protocol establishes a single common session key among the Vehicle, FN, and Cloud Server (CS), allowing the FN to access sensitive information exchanged between the Vehicle and the CS. To address these issues, we propose a quantum-resistant AKA protocol that establishes distinct pairwise session keys, thereby limiting the impact of FN compromise and protecting sensitive Vehicle–CS communications. Furthermore, the proposed protocol authenticates the Roadside Unit (RSU) involved in forwarding authentication messages, rather than treating it solely as an unauthenticated forwarding entity, thereby preventing unauthorized RSUs from participating in the authentication procedure. To provide resistance against quantum attacks, the proposed protocol employs Module Learning With Errors (MLWE)-based key establishment and Physical Unclonable Functions (PUFs) to protect long-term secret information. Its security is evaluated through Scyther verification, analysis in the Quantum Random Oracle Model (QROM), and informal security analysis, while NS-3 simulations are conducted to evaluate network performance. The results demonstrate that the proposed protocol provides secure and efficient authentication and key agreement for fog-based VANETs while mitigating security threats arising from FN compromise and quantum attacks.