Incentive Public Auditing Scheme with Identity-Based Designated Verifier in Cloud

With the rapid development of cloud storage and cloud computing technology, users can upload data to the cloud and share it with other users. However, the integrity and the privacy of data files at the cloud service provider suffer from challenges. In order to protect the data of user in the cloud, particularly for user groups without honest managers and semitrusted third-party auditors, we construct a new public auditing scheme that integrates a $(t,n)$ threshold signature, an incentive mechanism, an identity-based designated verifier group, blinding technology, and a multiblock signature technique. In our scheme, the $(t,n)$ threshold signature can eliminate the single power of the user group’s managers, to ensure that members of the user group take part in data sharing fairly and equally. The generation of a user’s key pairs and the signatures of data can be encouraged by an incentive mechanism based on a blockchain. Moreover, we introduce an identity-based designated verifier group and blinding technology to preserve data privacy during the data integrity auditing process. Furthermore, the multiblock signature technique reduces the costs to sign data blocks and verify. Finally, the security analysis and performance analysis demonstrate that our scheme is provably reliable and efficient.