<p>Currently, digital content stored in the cloud can easily meet the sharing needs of multiple users across different regions with the flexibility and efficiency of cloud storage technology. However, digital content stored in the cloud faces two major challenges: data integrity and data redundancy. Firstly, copyright data may be lost or damaged due to attacks or server system failures, compromising its integrity. Secondly, redundant copies of copyrighted data may exist in the cloud due to repeated uploads, leading to potential copyright disputes and affecting data consistency. To address these issues, this paper proposes a blockchain-based public audit scheme that enables deduplication for copyrighted data. We introduce the blockchain to replace the centralized the third-party auditor (TPA), ensuring the transparency of the auditing process and the immutability of the audit results. Due to the fairness of smart contracts, we ensure the fairness and accuracy of public audits by designing and introducing random challenge contracts and integrity verification contracts. At the same time, a novel deduplication method is introduced to enable users to confirm that redundant data in the cloud is safely deleted by generating audit logs and duplicate data deduplication proofs, thereby maintaining the uniqueness of copyright data. Experiments is conducted on Caliper’s Hyperledger Fabric v2.5 platform, and the effectiveness of this scheme is demonstrated by comparing the computational overhead and throughput.</p>