BFDAC: A Blockchain-Based and Fog-Computing-Assisted Data Access Control Scheme in Vehicular Social Networks

The vehicular social networks (VSNs) provide passengers, drivers and vehicles with multiple services, such as safe driving, data sharing, and traffic management. However, transmitting data in VSNs can expose information, such as the user’s identity and location. Malicious users who tamper with shared data can even cause serious traffic accidents. Considering the privacy protection and secure transmission of shared data in VSNs, we propose a blockchain-based and fog computing-assisted data access control (BFDAC) scheme. We combine the multi-authority ciphertext-policy attribute-based encryption algorithm with the consortium blockchain to avoid the security and trust issues in the form of centralized key management, and outsource part of the decryption calculations to roadside units (RSUs) as fog nodes to realize lightweight calculation for users. Our BFDAC scheme also supports user tracking and revocation, while users can also revoke shared data saved in the cloud. Security analysis shows that the BFDAC scheme can effectively protect the shared data. Experiments show that our BFDAC scheme reduces 32.8% in storage cost, 9.5% in encryption cost, and 57.1% in outsourced decryption cost compared to previous ones.