Recently there has been much interest in performing search queries over encrypted data to enable functionality while protecting sensitive data. One particularly efficient mechanism for executing such queries is order-preserving encryption encoding (OPE) which results in ciphertexts that preserve the relative order of the underlying plaintexts thus allowing range and comparison queries to be performed directly on ciphertexts. Recently, (SP 2013) gave the first construction of an ideally-secure OPE scheme and Kerschbaum (CCS 2015) showed how to achieve the even stronger notion of frequency-hiding OPE. However, as (CCS 2015) have recently demonstrated, these constructions remain vulnerable to several attacks. Additionally, all previous ideal OPE schemes (with or without frequency-hiding) either require a large round complexity of O(log n) rounds for each insertion, or a large persistent client storage of size O(n), where n is the number of items in the database. It is thus desirable to achieve a range query scheme addressing both issues gracefully. In this paper, we propose an alternative approach to range queries over encrypted data that is optimized to support insert-heavy workloads as are common in "big data" applications while still maintaining search functionality and achieving stronger security. Specifically, we propose a new primitive called partial order preserving encoding (POPE) that achieves ideal OPE security with frequency hiding and also leaves a sizable fraction of the data pairwise incomparable. Using only O(1) persistent and O(ne) non-persistent client storage for 0
Symmetric searchable encryption (SSE) was first proposed by Song, Wagner, and Perrig @cite_15 who showed how to search over encrypted data for keyword matches in sub-linear time. The first formal security definition for SSE was given by Goh @cite_45 , @cite_12 showed the first SSE scheme with sublinear search time and compact space, while @cite_39 showed the first SSE scheme with sublinear search time for conjunctive queries. Recent works @cite_10 @cite_28 @cite_36 achieve performance within a couple orders of magnitude of unencrypted databases for rich classes of queries including boolean formulas over keyword, and range queries. Of particular interest is the work of Hahn and Kerschbaum @cite_24 who show how to use lazy techniques to build SSE with quick updates. We refer interested readers to the survey by B "o @cite_30 for an excellent overview of this area.
@cite_30 @cite_28 @cite_36 @cite_39 @cite_24 @cite_45 @cite_15 @cite_10 @cite_12
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This work presents the design and analysis of the first searchable symmetric encryption (SSE) protocol that supports conjunctive search and general Boolean queries on outsourced symmetrically- encrypted data and that scales to very large databases and arbitrarily-structured data including free text search. To date, work in this area has focused mainly on single-keyword search. For the case of conjunctive search, prior SSE constructions required work linear in the total number of documents in the database and provided good privacy only for structured attribute-value data, rendering these solutions too slow and inflexible for large practical databases. Searchable symmetric encryption (SSE) allows a client to encrypt its data in such a way that this data can still be searched. The most immediate application of SSE is to cloud storage, where it enables a client to securely outsource its data to an untrusted cloud provider without sacrificing the ability to search over it. SSE has been the focus of active research and a multitude of schemes that achieve various levels of security and efficiency have been proposed. Any practical SSE scheme, however, should (at a minimum) satisfy the following properties: sublinear search time, security against adaptive chosen-keyword attacks, compact indexes and the ability to add and delete files efficiently. Unfortunately, none of the previously-known SSE constructions achieve all these properties at the same time. This severely limits the practical value of SSE and decreases its chance of deployment in real-world cloud storage systems. To address this, we propose the first SSE scheme to satisfy all the properties outlined above. Our construction extends the inverted index approach (, CCS 2006) in several non-trivial ways and introduces new techniques for the design of SSE. In addition, we implement our scheme and conduct a performance evaluation, showing that our approach is highly efficient and ready for deployment. We survey the notion of provably secure searchable encryption (SE) by giving a complete and comprehensive overview of the two main SE techniques: searchable symmetric encryption (SSE) and public key encryption with keyword search (PEKS). Since the pioneering work of Song, Wagner, and Perrig (IEEE S&P '00), the field of provably secure SE has expanded to the point where we felt that taking stock would provide benefit to the community. The survey has been written primarily for the nonspecialist who has a basic information security background. Thus, we sacrifice full details and proofs of individual constructions in favor of an overview of the underlying key techniques. We categorize and compare the different SE schemes in terms of their security, efficiency, and functionality. For the experienced researcher, we point out connections between the many approaches to SE and identify open research problems. Two major conclusions can be drawn from our work. While the so-called IND-CKA2 security notion becomes prevalent in the literature and efficient (sublinear) SE schemes meeting this notion exist in the symmetric setting, achieving this strong form of security efficiently in the asymmetric setting remains an open problem. We observe that in multirecipient SE schemes, regardless of their efficiency drawbacks, there is a noticeable lack of query expressiveness that hinders deployment in practice. A Searchable Symmetric Encryption (SSE) scheme allows a server to search a user's data without having to decrypt the data. This provides the user with a high degree of privacy and is particularly useful when data is stored on Cloud. Numerous SSE schemes have already been proposed and while most have excellent security properties, few meet high performance requirements and most only support searching for a single keyword at a time. The SSE scheme of (CRYPTO 2013) is notable for its high efficiency on restricted forms of Boolean queries, but has low efficiency for, or does not support, other common forms of boolean queries. In this paper, we propose a generalization and optimization of the SSE scheme, which extends to support a much larger class of boolean queries, and performs no worse, and often with much higher efficiency than the scheme for the remaining queries.