Privacy-Preserving and Secure Distributed Data Sharing Scheme for VANETs

Data sharing is one of the essential services of vehicular ad hoc networks (VANETs), which primarily requires data security and access control, and ciphertext-policy attribute-based encryption (CP-ABE) is a promising tool. However, data sharing schemes of distributed CP-ABE have concerns about the single-point performance bottleneck and privacy leakage. The factor for the former is that the authority manages a disjoint attribute set. The latter is because the user's identity and attributes are required to submit to authorities, which targets to bind this information to decryption keys for collusion-resistant. We propose a privacy-preserving distributed data sharing scheme for VANETs. This scheme introduces asymmetric group key agreement to distributed CP-ABE, which realizes that multiple authorities manage an attribute, and the user can obtain the attribute key bound with his identity from any authority in the group. To match up to the requirement of privacy-preserving, a key extract protocol provided user anonymity is proposed, which implements that attribute keys can be obtained without revealing the user's identity and attributes. Moreover, partial policy hiding is satisfied. Finally, we analyze and evaluate the proposed scheme, and the results indicate that our scheme is secure and efficient.

I. Introduction

With wireless communication protocols, vehicles in vehicular ad hoc networks (VANETs) can communicate with other entities to obtain continuous and stable network service, and further, various smart services and applications can be obtained [1]. Data sharing is one of the essential and practical services in VANETs, including sharing of traffic conditions, weather variables, driving assistance, navigation support, entertainment content, etc [1], [2], which can effectively improve traffic conditions and user experience. It is worth noting that large-scale data sharing in VANETs requires vehicles to have certain computing power and a platform to support sharing data. Fortunately, hardware devices and embedded systems installed in vehicles give the opportunity to pool resources [3]. Moreover, cloud storage and computing technologies provide a platform and computing resource for vehicles to access data [2].