Side Channel Attack resistant Cross-User Generalized Deduplication for Cloud Storage

Cross-user deduplication is an effective technique to improve the efficiency of cloud storage by blocking redundant uploading of duplicate data. However, the deterministic response of this technique actually creates a side channel for attackers, which is able to be utilized to infer existence privacy of the target data in cloud storage. Because of the difficulty in achieving complete obfuscation in deduplication response, such kind of attack still cannot be well resisted, thus is becoming a big obstacle in using this technique. To deal with this challenge, we propose a cross-user generalized deduplication scheme for cloud storage, which takes the lead to achieve security against side channel attack by template extraction strategy. Specifically, we perform source-based deduplication to extracted templates and target-based strategy to the corresponding deviations. Because of the generalization strategy introduced, existence privacy of the target file cannot be inferred from deduplication response any more. The experimental results show that, with security against side channel attack guaranteed, the proposed scheme is more efficient in both communication and storage comparing with the state-of-the art.