Abstract
Data deduplication is a technique to eliminate duplicate data in order to save storage space and enlarge upload bandwidth, which has been applied by cloud storage systems. However, a cloud storage provider (CSP) may tamper user data or cheat users to pay unused storage for duplicate data that are only stored once. Although previous solutions adopt message-locked encryption along with Proof of Retrievability (PoR) to check the integrity of deduplicated encrypted data, they ignore proving the correctness of duplication check during data upload and require the same file to be derived into same verification tags, which suffers from brute-force attacks and restricts users from flexibly creating their own individual verification tags. In this paper, we propose a verifiable deduplication scheme called VeriDedup to address the above problems. It can guarantee the correctness of duplication check and support flexible tag generation for integrity check over encrypted data deduplication in an integrative way. Concretely, we propose a novel Tag-flexible Deduplication-supported Integrity Check Protocol (TDICP) based on Private Information Retrieval (PIR) by introducing a novel verification tag called <inline-formula><tex-math notation="LaTeX">${note\ set}$</tex-math></inline-formula> , which allows multiple users holding the same file to generate their individual verification tags and still supports tag deduplication at the CSP. Furthermore, we make the first attempt to guarantee the correctness of data duplication check by introducing a novel User Determined Duplication Check Protocol (UDDCP) based on Private Set Intersection (PSI), which can resist a CSP from providing a fake duplication check result to users. Security analysis shows the correctness and soundness of our scheme. Simulation studies based on real data show the efficacy and efficiency of our proposed scheme and its significant advantages over prior arts.
Highlights
C LOUD computing has become a popular information technology service by providing huge amount of resources to end users based on their demands
Tag-flexible Deduplication-supported Integrity Check Protocol (TDICP) allows users to generate their own individual verification tags for integrity check while the verification tags can be deduplicated at the cloud storage provider (CSP) different. We propose another novel protocol named User Determined Duplication Check Protocol (UDDCP) to guarantee the correctness of duplication check based on Private Set Intersection (PSI), so that the CSP is impossible to cheat the user to pay for unused storage space due to deduplication
We applied five metrics in our simulation studies to evaluate TDICP, including (1) the data owner’s computational complexity for creating and inserting the note set; (2) the data holder’s storage overhead for extra data storage in integrity check; (3) the data holder’s computational complexity for challenging CSP and retrieving the inserted note set for verification; (4) CSP computational complexity for responding the challenge from the data holder; (5) Data holder-CSP communication cost for transferring extra data in integrity check
Summary
C LOUD computing has become a popular information technology service by providing huge amount of resources (e.g., storage and computing) to end users based on their demands. Since the volume of data in the world is increasing rapidly, saving cloud storage becomes essential. One of the key reasons that causes storage waste is duplicate data storage. Multiple users may save same files or different files containing same pieces of data blocks at the cloud. Duplicate data storage at the cloud introduces a big waste of storage resources. The CSP can cooperate with the cloud user to first check whether a pending uploaded file has been saved already or not, and provide the user whose pieces of file data are checked duplicate a way to access the file without storing another copy at the cloud
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