A Secure and Verifiable Data Sharing Scheme Based on Blockchain in Vehicular Social Networks

The vehicular social networks (VSNs) supports diverse kinds of services such as traffic management, road safety, and sharing data (videos, audios, roads photos, air quality, and so on). However, its complex, large-scale and dynamic network structure poses new security challenges. Among these challenges, secure data transmission has turned to be a spotlight. Ciphertext-policy attribute-based encryption (CP-ABE) may be adopted to realize one-to-many data sharing in VSNs. In traditional CP-ABE schemes, access policy is stored and granted by the could, which lacks credibility due to centralization. In this article, we propose a secure and verifiable one-to-many data sharing scheme to solve the above problem. We use blockchain to record the access policy, realizing user self-certification and cloud non-repudiation. Considering the computing capabilities of the vehicular user, we propose an effective scheme for certificating. Meanwhile, considering the sensitive information included in the access policy, we propose a policy hiding scheme. Our scheme also supports data revocation when a vehicular user no longer wants to share the data in VSNs. Finally, security analysis and simulation show our scheme is both secure and efficient.