A Cloud Data Integrity Verification Scheme Based on Blockchain

Cloud storage saves a lot of storage overheads for users to manage data. However, it also brings data integrity challenges. Relying only on message authentication codes (MAC) and hash functions introduces serious communication overheads. Existing integrity verification schemes usually rely on third-party auditors (TPAs) to reduce users' audit burden. However, malicious TPAs not only extract raw data from repeated audit processes but also collude with a cloud server to launch collusive attacks. Recently, some integrity verification schemes based on blockchain are presented to solve challenges of raw data extraction and collusive attacks. These schemes cannot realize large-scale data processing on a blockchain as well as dynamic data operations. To address the above issues, we propose a blockchain-based cloud data integrity verification scheme (BCD-IV) that removes TPAs by using chain-code that solves collusive attacks. Furthermore, we construct a new homomorphic verification tag (HVT) based on the signature proposed by Zhang, Safavi, and Susilo (ZSS), which supports blockless verification. The proposed scheme realizes full dynamic operations with auxiliary information that stores on a blockchain. Mathematical analysis shows that our scheme has lower complexity in terms of communication and computation overhead, which are both O(c). Finally, we conduct experiments on Hyperledger Fabric V2.2 to demonstrate that the computation efficiency of audit is the highest compared to the state-of-the-art and the storage overhead is negligible.