Blockchain-Assisted Conditional Anonymity Privacy-Preserving Public Auditing Scheme With Reward Mechanism

In real-world scenarios, in order to encourage one to report others crimes, judicial department usually rents independent cloud storage spaces to receive the precious evidences from whistleblowers. Since the uploaded data are not controlled by cloud users, remote data integrity is very important. Public cloud auditing enables an auditor to periodically check the integrity of outsourcing data on behalf of users, without retrieving the entire data file. However, most existing data auditing schemes have potential security vulnerabilities, and thus cannot defense many security attacks (e.g., the man-in-the-middle attack). Meanwhile, it is significant to protect whistleblower's identity privacy, reward the real data uploader, and further trace the responsibility of slanders accurately. From the aforementioned requirements, we present an efficient blockchain-assisted conditional anonymity privacy-preserving public auditing (BA-CAPPPA) scheme with reward mechanism. The Ethereum blockchain is integrated into BA-CAPPPA to enhance the security level of the whole public auditing mechanism. Theoretical analysis results show that the BA-CAPPPA achieves man-in-the-middle attack resistance, storage correctness guarantee, data privacy-preservation, conditional identity anonymity, and reward mechanism. Performance evaluations and comparisons demonstrate that BA-CAPPPA could outperform some state-of-the-art data auditing schemes.