Data Integrity Verification Scheme for Privacy Protection and Fair Payment

With the emergence of cloud storage, increasing users tend to migrate their data to cloud for management and maintenance, which can save time and money on the series of work. To ensure the integrity of data stored in the efficient yet unreliable cloud, data owners may adopt a data integrity verification model. In the pay-per-use cloud environment, data owners not only pay for the service to cloud server provider, but also pay an additional fee to the third party auditor (TPA) in order to perform verification operations. However, TPA is not always available in the actual, which makes the integrity of data become a potential vulnerability. In view of the untrustworthy of TPA and the realization of service-payment fairness, we propose a novel verification scheme for privacy protection and fair payment. Firstly, we introduce a novel type of data authentication structure—the rank-based Merkle Hash tree to realize the integrity verification of data index and support verifiable dynamic update of block. Secondly, in order to achieve privacy protection and reduce communication overhead, a non-interactive dynamic provable data possession is presented. Finally, combined with blockchain, smart contract is applied to achieve service-payment fairness among data owners, cloud storage server and TPA, so that all parties can act honestly according to the rules. Performance analysis and experiments show that the proposed scheme can effectively protect the privacy of user data, realize fair payment, and achieve lower computational cost and communication overhead of the entire system.