BlockShare: A Blockchain Empowered System for Privacy-Preserving Verifiable Data Sharing

Data has become the most valuable resource, as it is essential to analytics, decision making, and artificial intelligence. To unleash the value of data, data sharing has become a prerequisite to bringing tremendous benefits for both data providers and data consumers. However, existing solutions for data sharing are mostly server-centric, i.e., they rely on the control of a trusted server, which increases security and privacy concerns among data users. The design of a privacy-preserving verifiable data sharing framework to simultaneously secure user privacy and data integrity has not been sufficiently studied and remains a grand challenge. In this paper, we propose BlockShare, a privacy-preserving verifiable data sharing system based on blockchain. First, we design a novel blockchain-based architecture, together with a new authenticated data structure scheme to efficiently verify any portion of a shared data record in a decentralized fashion. Second, we develop a zero-knowledge verification scheme that enables a user to prove a dynamic condition without disclosing the specific data attribute, minimizing privacy loss. We implement BlockShare and conduct experiments to evaluate the system performance. Experimental results demonstrate the effectiveness of our proposed system.