Key Transferring-Based Secure Deduplication for Cloud Storage With Resistance Against Brute-Force Attacks

Convergent encryption is an effective technique to achieve cross-user deduplication of encrypted data in cloud storage. However, it is vulnerable to brute-force attacks for data with low min-entropy. Moreover, once the content of the target data is successfully constructed through the aforementioned attacks, the corresponding index can also be obtained, leading to the risk of violating privacy during the process of data downloading. To address these challenges, we propose a key transferring-based secure deduplication (KTSD) scheme for cloud storage with support for ownership verification, which significantly improves the security against brute-force attacks during the ciphertext deduplication and downloading. Specifically, we introduce a randomly generated key in data encryption and downloading index generation to prevent the results from being inferred. And define a deduplication request index and a key request index by using the bloom filter to achieve brute-force attack resistant key transferring. An RSA-based ownership verification scheme is designed for the downloading process to effectively prevent privacy leakage. Finally, we prove the security of our schemes by security analysis and perform the performance evaluation experiments, the results of which show that compared to the state-of-the art, the cloud storage overhead can be reduced by 6.01% to 20.49% under KTSD.