A Blockchain-Based Efficient Data Integrity Verification Scheme in Multi-Cloud Storage

The cloud storage service provides the storage and access function for massive data, reducing the management cost for large amounts of data. The data integrity verification scheme in cloud storage can be employed to help users confirm the integrity of outsourced data. Although public data integrity verification schemes allow users to outsource data integrity verification to third-party auditor (TPA), there are still many problems with centralized TPA in terms of security and efficiency. In recent years, researchers have tried to apply blockchain technology to solve the centralization problem of traditional methods, but these schemes do not pay attention to the problem of efficiency degradation caused by the use of blockchain technology. This paper proposes an efficient data integrity verification scheme for multi-cloud storage services by using blockchain technology. The overall verification can verify the integrity of multiple CSPs, which solves the problems of low computational efficiency. Local verification can trace the source to the specific damaged CSP, which is more secure and reliable. In addition, this paper puts the data verification process directly in the blockchain for public execution and provides data integrity verification services without the assistance of any third-party audit platform, avoiding the security problems caused by untrusted TPA. Theoretical analysis and experiments verify the safety and effectiveness of the scheme.