Public Audit Scheme of Shared Data Based on Blockchain

A cloud platform provides users with shared data storage services. While the cloud protects the privacy of users, it is inevitable that malicious users illegally use shared data. Currently, the audit scheme in which managing users access records by group managers is widely adopted, and this scheme realizes the protection of users’ identity privacy and the traceability of users’ identities. However, this kind of scheme disregards the hidden danger of group managers and has certain limitations. This paper proposes a public audit scheme of shared data based on the blockchain (BBSD). First, by introducing the blockchain technology, this paper realizes the sharing of records information, avoids the hidden security risks of group managers, and simultaneously makes the user identity traceable. Second, this paper constructs a novel audit algorithm to preprocess users’ revocation, which adopts a new resignature algorithm to make management more secure and reliable. Then, this paper introduces an outsourcing algorithm to reduce the computational burden of users. Finally, the theoretical analysis and experimental verification show that BBSD is secure and efficient.