Cloud storage enables applications to efficiently manage their remote data but facing the risk of being tampered with. This paper utilizes blockchain technique to develop a novel public auditing scheme for verifying data integrity in cloud storage. In the proposed scheme, different from the existing works that involve three participatory entities, only two predefined entities (i.e. data owner and cloud service provider) who may not trust each other are involved, and the third party auditor for data auditing is removed. Specifically, data owners store the lightweight verification tags on the blockchain and generate a proof by constructing the Merkle Hash Tree using the hashtags to reduce the overhead of computation and communication for integrity verification. Besides, this work is able to achieve 100% confidence of auditing theoretically, as the hashtag of each data block is utilized to build the Merkle Hash Tree for the data integrity verification. Security analysis shows that the proposed scheme can defend against malicious entities and the 51% attack. Experimental results demonstrate the significant improvements on computation and communication.

云存储使应用程序可以有效地管理其远程数据，但面临被篡改的风险。本文利用区块链技术开发了一种新颖的公共审计方案，以验证云存储中的数据完整性。在提议的方案中，与涉及三个参与实体的现有作品不同，仅涉及可能互不信任的两个预定义实体（即数据所有者和云服务提供商），并且删除了用于数据审核的第三方审核员。具体来说，数据所有者将轻量级验证标签存储在区块链上，并通过使用井号标签构建Merkle哈希树来生成证明，以减少完整性验证的计算和通信开销。此外，这项工作理论上可以达到100％的审计信心，因为每个数据块的主题标签都用于构建Merkle哈希树以进行数据完整性验证。安全分析表明，该方案可以防御恶意实体和51％的攻击。实验结果证明了在计算和通信方面的重大改进。