Enable Owner Transfer and Data Traceability in Public Auditing Scheme for Cloud Digital Content

Currently, sharing digital content significantly enhances the value of data, and data purchasing serves as a means of realizing this value after sharing. After a data purchase transaction occurs, although the ownership of the data has been successfully transferred, this process introduces two major challenges: first, maintaining the continuity of cloud data integrity verification after ownership transfers, and second, enabling full-lifecycle traceability of data to clarify copyright attribution. To address these issues, this paper proposes a public auditing scheme that supports both cloud data ownership transfer and data traceability. First, the proposed scheme introduces an update factor as a mathematical structure to enable the update of HVT (homomorphic verifiable tag) on the cloud. Meanwhile, the CS (cloud service) performs tag update computations, thereby ensuring security while reducing the computational and communication overhead for local users. Furthermore, to achieve transparency throughout the data's lifecycle, copyright information of digital content is embedded into blockchain transactions. A data traceability strategy is then designed leveraging a chameleon hash function, and a detailed traceability process is presented. Security analysis demonstrates that our scheme satisfies correctness and reliability, and a series of comparative experiments further validate its feasibility and efficiency in practical applications.