Leakage Resilient Proofs of Ownership in Cloud Storage, Revisited

Abstract

Abstract. Client-side deduplication is a very effective mechanism to reduce both storage and communication cost in cloud storage service. Halevi et al. (CCS '11) discovered security vulnerability in existing implementation of client-side deduplication and proposed a cryptographic primitive called "proofs of ownership" (PoW) as a countermeasure. In a proof of ownership scheme, any owner of the same file can prove to the cloud storage server that he/she owns that file in an efficient and secure manner, even if a bounded amount of any efficiently extractable information of that file has been leaked. We revisit Halevi et al.'s formulation of PoW and significantly improve the understanding and construction of PoW. Our contribution is twofold:• Firstly, we propose a generic and conceptually simple approach to construct Privacy-Preserving Proofs of Ownership scheme, by leveraging on well-known primitives (i.e. Randomness Extractor and Proofs of Retrievability) and technique (i.e. sample-then-extract). Our approach can be roughly described as Privacy-Preserving PoW = Randomness Extractor + Proofs of Retrievability.• Secondly, in order to provide a better instantiation of Privacy-Preserving-PoW, we propose a novel design of randomness extractor with large output size, which improves the state of art by reducing both the random seed length and entropy loss (i.e. the difference between the entropy of input and output) simultaneously.

An efficient confidentiality-preserving Proof of Ownership for deduplication

“…By contrast, more challenging proposals address both problems, namely, they build a PoW scheme and offer protection against honest-but-curious servers (Xu and Zhou, 2014;Li et al, 2014a;Stanek et al, 2013;jin et al, 2013;Ng et al, 2012). Furthermore, Xu and Zhou (2014), Stanek et al (2013), and Ng et al (2012) provide a formal security analysis and Stanek et al (2013) focus on server storage efficiency as well.…”

“…In the context of file systems, the combination of data confidentiality and data deduplication was introduced by Douceur et al (2002). Given that hashes are public data, the original CE scheme is not secure (Storer et al, 2008;Xu and Zhou, 2014) and thus, different approaches apply variations to the original scheme.…”

“…Xu et al proposed a CE scheme in which files are encrypted with an AES random key τ, which is in turn encrypted using the file hash as key obtaining C τ (Xu and Zhou, 2014). In the first upload of a file, the file hash, hash(F), the encrypted file C F and C τ are provided to the server.…”

ase-PoW: A Proof of Ownership Mechanism for Cloud Deduplication in Hierarchical Environments

“…For example, the PoW schemes in [24,25,26,15,17,27] are designed to work with honest-but-curious servers. Due to the use of CE in many existing PoW schemes such as [25,26,16,17,22], these schemes are not secure against content analysis attacks as previously discussed [16]. A number of proposals to avoid such pitfalls has also been proposed in recent years.…”

Privacy preserving proof of ownership for data in cloud storage systems

“…This process will help the cloud storage provider to verify the duplication of the data items, without knowing the corresponding original content of the file. As several users are using the cloud storage to archive their data items [19] [20], ensuring privacy [2] [18] [9] of the data items and the users is essential. However, verification of duplicate data items leaks the privacy of the data items and the users, i.e process of verifying the redundant data items is not compatible with the conventional way of converting the data into secret form using symmetric key encryption.…”