Abstract
Vehicular Ad-Hoc Networks (VANETs) play an increasingly critical role in modern transportation systems, yet they face significant security challenges, particularly in privacy preservation and efficient emergency responses. Current solutions remain constrained by several limitations, including high computational overhead on resource-constrained vehicular devices, vulnerabilities in anonymous authentication mechanisms prone to linkage attacks, and inadequate handling of emergency information. To overcome these challenges, we propose a lightweight, distributed data-sharing scheme that employs constant Type-III pairing operations for encryption and decryption, ensuring efficient processing even on embedded systems. Additionally, existing methods for accident traceability often fail to accurately determine incident causes. Our framework addresses this issue by introducing an emergency-aware proxy re-encryption mechanism, enabling temporary access privilege escalation for vehicles managing accident-related data. The proposed scheme adopts a hierarchical multi-authority architecture and integrates a dual anonymity mechanism through enhanced group signatures and attribute-based anonymous techniques. Identity disclosure requires multi-authority consensus, while a privacy-preserving attribute management system safeguards sensitive data anonymity. Security analysis and experimental evaluations confirm the robustness of our approach, demonstrating its suitability and resilience for deployment in VANET environments.