Experimental Evaluation of Fully Homomorphic Encryption for Privacy-Preserving V2X Communication

Abstract

Vehicle-to-Everything (V2X) communication requires continuous exchange of mobility data, but this information is highly sensitive and must be protected. Fully Homomorphic Encryption (FHE) enables computation directly on encrypted data and has recently been explored for Intelligent Transportation Systems (ITS), yet its practical feasibility for specific V2X tasks remains unclear. This paper experimentally evaluates three lattice-based schemes (BFV, BGV, CKKS) using OpenFHE on SUMO-generated mobility data. Three representative traffic-related tasks are considered: collision-risk detection, average speed estimation, and traffic density. For each scheme, we measure encryption time, homomorphic computation time, decryption time, ciphertext size, and correctness relative to plaintext baselines. The results show that all schemes achieve near-perfect correctness, and that aggregated analytics (average speed, density) complete well within non-safety-critical time budgets. However, all schemes consume a significant portion of the 100 ms safety message threshold. These findings quantify the current performance–privacy trade-offs of FHE in V2X scenarios and indicate that hardware acceleration or lighter cryptographic configurations are needed for real-time safety applications.