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... that do not require scanning the entire database and could be used to process certain restricted SQL queries. Bao et al. [3] extend these encrypted search methods to the multi-user case. Yang et al. =-=[51]-=- run selections with equality predicates over encrypted data. Evdokimov and Guenther present methods for the same selections, as well as Cartesian products and projections [15]. Agrawal et al. develop...

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... query and the index. However, most existing solutions of SE lack the above query flexibility or do not bear enough efficiency. Early works mostly only support single-keyword search [18], [14], [15], =-=[37]-=-. Later, several multi-keyword search schemes were proposed [19], [5], [11], [33], [21], [32], [22], [34], [13] that enable conjunctive or disjunctive search formulas. It usually incurs high computati...

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...basic idea is to generate a keyed hash for the keywords and store this information inside the ciphertext. The server can search the keywords by recalculating and matching the hash value. Yang et. al. =-=[4]-=- proposed an elegant scheme for performing queries on encrypted data and also provided a secure index to speed up queries by two-step mapping. Goh’s scheme [5] enables searches on encrypted data by co...

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...needed for applications. Past work in the field of untrusted databases assumes an untrusted server and a trusted client. Security in this model can be done with information dissociation or encryption =-=[11, 16, 12]-=-. Our scenario is the reverse. Backstrom, Dwork, and Kleinberg describe sophisticated active and passive attacks on anonymous social graphs. Their goal is to determine whether two given known nodes ar...

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...eded for applications. Past work in the field of untrusted databases assumes 7an untrusted server and a trusted client. Security in this model can be done with information dissociation or encryption =-=[13, 18, 14]-=-. Our scenario is the reverse. 8. CONCLUSIONS The Facebook Platform has proven wildly popular, and the potential for profit due to increased user interactivity has caused other large social networking...

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... years, researchers have developed cryptographic tools for searching keywords over encrypted text [4, 43] and some researchers have proposed using these tools to process SQL queries on encrypted data =-=[2, 5, 14, 51]-=-. These approaches are a good first cut at the problem, but are incomplete in substantive ways: they do not support many basic SQL queries, providing mostly only equality comparisons, most of them req...

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...t of querying the encrypted data. Neither the data should be revealed nor the query itself. This can be addressed by a searchable encryption scheme. Examples of such searchable encryption schemes are =-=[8, 10, 11, 12, 25]-=-. All these schemes allow searching for keywords on a secret-key encrypted database without revealing the keyword. Note that for efficiency all schemes leak the access pattern, i.e. the documents (or ...

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...ve query transformations. Another approach we have not investigated so far is “encryption with subkeys” by Davida et al. (see [11]). While in this article we only cover join queries, Yang et al. (see =-=[24]-=-) analyze selection queries over a table in an outsourced database. Unlike the DAS model, they encrypt each attribute value (that is, each table cell) separately. Each encrypted value also has a “chec...

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...ncy analysis and sorting). Unlike standard security definitions, however, the security notions proposed in [37] are attackspecific (e.g., they define security only against frequency analysis) and guarantee only one-wayness; as opposed to standard cryptographic notions which guarantee that partial information is protected. Finally, [37] also proposes deterministic and probabilistic OPE variants. The deterministic variant is still vulnerable to our attacks (albeit requiring larger encrypted columns). There is an extensive literature on OPE variants including probabilistic OPE, modular OPE, etc. [20, 23,27, 28,32, 40]. As far as we know, none of these constructions are used in any EDB system. We leave it as future work to assess the efficacy of our attacks against these variants. 3. PRELIMINARIES Relational databases. A relational database is a collection of tables where each row corresponds to an entity (e.g., a customer or an employee) and each column corresponds to an attribute (e.g., age, height, salary). For any given attribute, we refer to the set of all possible values that it can take as its space. The attribute space of a column is the space of that column’s attribute. If a column supports equalit...

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...d server and later search for a specific keyword by giving the server a search capability, that does not reveal the keyword or any plaintext. Its security and efficiency was later improved in [8] and =-=[9]-=-. Golle, et al. [10] developed a symmetric-key version of SoE that supports conjunctive keyword search. Boneh, et al. [11] later proposed a public-key version of encryption with keyword search (PEKS),...