A Lightweight Key Agreement Protocol for V2X Communications Based on Kyber and Saber

Abstract

Highlights: What are the main findings? A hybrid post-quantum key agreement protocol is proposed for V2X environments, combining Kyber and Saber to enhance both security and computational efficiency. The protocol achieves authenticated key exchange with low handshake latency, verified through Veins + SUMO simulations, and integrates algorithm-level optimizations for embedded platforms to enhance efficiency and adaptability. What are the implications of the main findings? The protocol shows high adaptability to dynamic and low-power vehicular environments, supporting secure and efficient key exchange under quantum threats. It provides a practical and forward-compatible cryptographic framework for intelligent transportation systems in the post-quantum era. This paper proposes a post-quantum secure key agreement protocol tailored for vehicular networks (V2X), addressing the dual challenges of quantum resistance and lightweight deployment. The hybrid scheme integrates two lattice-based Key Encapsulation Mechanisms (KEMs)—Kyber and Saber—to construct a dual-path handshake framework that enhances cryptographic redundancy and ensures robustness against quantum attacks. The protocol achieves secure and authenticated key exchange through RSU public-key broadcasting, OBU dual-path encapsulation, and session-key derivation using HMAC and timestamps. To support efficient execution in embedded vehicular environments, several algorithm-level optimizations are incorporated, including Number Theoretic Transform (NTT) acceleration for Kyber, AVX2-based parallelism for Saber, and integer inner-product techniques to minimize computational overhead. Experimental validation on a Veins + SUMO vehicular simulation platform demonstrates that the proposed protocol reduces handshake latency by nearly 60% compared with RSA, achieves delay performance comparable to ECDH, and lowers total resource consumption by around 40%. These results confirm that the Kyber + Saber hybrid protocol provides a practical, scalable, and quantum-resistant solution for secure V2X communication in dynamic, resource-constrained, and latency-sensitive environments.