BCADS: Blockchain-Assisted Cross-Domain Authentication with Decentralized Identity for VANETs under Strict Oversight

Cross-domain authentication is essential for se curing communication between different management domains in Vehicular Ad Hoc Networks (VANETs). However, existing blockchain-based cross-domain authentication schemes, which rely on centralized entities or smart contracts for distributed identity management, face challenges in terms of latency, trust assumptions, security guarantees, and deployment flexibility. Furthermore, many of these schemes do not fully meet the stringent regulatory requirements of real-world VANET sce narios and provide limited protection of vehicle privacy. In this paper, we introduce BCADS, a Blockchain-assisted Cross domain Authentication with Decentralized identity for VANETs under Strict oversight. BCADS enables vehicles to autonomously generate and manage their identifiers, eliminating reliance on a single centralized authority and mitigating single points of failure by jointly maintaining identity records on a consortium blockchain infrastructure. In addition, BCADS is designed to accommodate regulatory mandates while protecting user privacy and data confidentiality. The scheme addresses key limitations of prior designs by supporting flexible identity management and strong privacy protection within a practical architecture. Security analysis shows that BCADS withstands a broad range of attacks and achieves the desired security properties. Performance measurements and simulation experiments indicate that BCADS reduces computational costs by up to 36.6% and communication costs by up to 87.1%, demonstrating its practicality for deployment in real-world VANETs.