Abstract
Vehicular ad-hoc networks (VANETs) are pivotal in advancing intelligent driving and enhancing vehicular services. However, they introduce significant risks of data privacy breaches. Although numerous data sharing mechanisms have been proposed, they often suffer from issues such as excessive central authority power, collusion among authorities leading to key leakage, and vulnerabilities to message linking attacks that can facilitate deliberate traffic incidents. Additionally, malicious cloud entities may cause data sharing failures through improper decryption, and the substantial computational overhead is ill-suited for resource-constrained vehicles. To address these challenges, we propose a lightweight data sharing scheme based on decentralized ciphertext-policy attribute-based encryption scheme tailored for VANETs. Our approach leverages Type-III asymmetric groups to centralize the majority of user computations within a more compact group structure. By utilizing an edge computing frame work, we outsource computation-intensive pairing operations to the cloud in a verifiable manner, ensuring that the complexity of access policies does not linearly impact pairing computations. Furthermore, we implement ring signatures to facilitate anony mous communication between vehicles and employ a garbled bloom filter to obscure access policies. A consortium blockchain is deployed to manage multiple attribute authority nodes, which utilize the practical byzantine fault tolerance (PBFT) consensus mechanism for secure revocation processes, thereby preventing malicious or erroneous revocations. Comprehensive security assessments and performance evaluations validate the efficiency and robustness of our scheme within the VANETs environment.
