Efficient data possession–checking protocol with deduplication in cloud

Deduplication has been widely applied to save storage overhead in the cloud server. Data integrity verification with deduplication can not only save space of the cloud server but also ensure security of the stored data. In the existing integrity verification scheme, deduplications are implemented by the cloud server. The signatures of all data blocks are generated and sent to the cloud server. Once receiving the data blocks and signatures, the cloud server compares the received signatures with the stored signatures. If there is a signature that has the same value as some stored signature, the received signature and data block will not be stored by the cloud server. Otherwise, the cloud server stores all received signatures and data blocks. In fact, these operations bring a lot of computational costs. To solve this problem, we propose a data integrity verification scheme with deduplication. In this scheme, the deduplication is performed by the cloud users, which can avoid additional communicational and computational costs. The experiment evaluation indicates that our scheme is practical for real application scenario. We demonstrate that the proposed scheme satisfies signature unforgeability, and the malicious users cannot obtain any legitimate file from the cloud server in the form of deception.