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Security and Privacy in Search Services.

机译:搜索服务中的安全性和隐私权。

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摘要

In the first part of this dissertation, we show how to execute range queries securely and efficiently on encrypted databases in the cloud. Current methods provide either security or efficiency, but not both. Many schemes even reveal the ordering of encrypted tuples, which, as we show, allows adversaries to estimate plaintext values accurately. We present the Rˆ-tree, a hierarchical encrypted index that may be securely placed in the cloud, and searched efficiently. It is based on a mechanism we design for encrypted halfspace range queries in Rd, using Asymmetric Scalar-product Preserving Encryption. Data owners can tune the Rˆ-tree parameters to achieve desired security-efficiency tradeoffs. We also present extensive experiments to evaluate Rˆ-tree performance. Our results show that Rˆ-tree queries are efficient on encrypted databases, and reveal far less information than competing methods. In the second part, we propose a new query obfuscation scheme to protect user privacy in key word search. Text-based search queries reveal user intent to the search engine, compromising privacy. Topical Intent Obfuscation (TIO) is a promising new approach to preserving user privacy. TIO masks topical intent by mixing real user queries with dummy queries matching various different topics. Dummy queries are generated using a Dummy Query Generation Algorithm (DGA). We demonstrate various shortcomings in current TIO schemes, and show how to correct them. Current schemes assume that DGA details are unknown to the adversary. We argue that this is a flawed assumption, and show how DGA details can be used to construct efficient attacks on TIO schemes, using an iterative DGA as an example. Our extensive experiments on real data sets show that our attacks can flag up to 80% of dummy queries. We also propose HDGA, a new DGA that we prove to be immune to the attacks based on DGA semantics that we describe.
机译:在本文的第一部分,我们展示了如何在云中的加密数据库上安全有效地执行范围查询。当前的方法提供安全性或效率,但不能同时提供两者。许多方案甚至揭示了加密元组的顺序,正如我们所展示的,这使攻击者可以准确地估计明文值。我们提出了Rˆ树,这是一种可以安全地放置在云中并进行有效搜索的分层加密索引。它基于我们使用非对称标量乘积保存加密为Rd中的加密半空间范围查询设计的机制。数据所有者可以调整R the树参数,以实现所需的安全效率折衷。我们还提出了广泛的实验来评估Rˆ树的性能。我们的结果表明,Rˆ树查询在加密数据库上非常有效,并且比竞争方法揭示的信息少得多。在第二部分中,我们提出了一种新的查询混淆方案,以保护关键字搜索中的用户隐私。基于文本的搜索查询向搜索引擎揭示了用户意图,从而损害了隐私。主题意图混淆(TIO)是一种有前途的保护用户隐私的新方法。 TIO通过将真实用户查询与匹配各种不同主题的虚拟查询混合在一起来掩盖主题意图。虚拟查询是使用虚拟查询生成算法(DGA)生成的。我们展示了当前TIO方案中的各种缺陷,并展示了如何纠正它们。当前方案假定DGA详细信息对对手是未知的。我们认为这是一个错误的假设,并以迭代DGA为例,说明如何使用DGA详细信息来构造对TIO方案的有效攻击。我们对真实数据集进行的广泛实验表明,我们的攻击最多可以标记80%的虚拟查询。我们还提出了HDGA,这是一种新的DGA,基于我们描述的DGA语义,我们证明它不受攻击。

著录项

  • 作者

    Wang, Peng.;

  • 作者单位

    University of California, Riverside.;

  • 授予单位 University of California, Riverside.;
  • 学科 Computer Science.;Engineering General.;Information Science.
  • 学位 Ph.D.
  • 年度 2014
  • 页码 106 p.
  • 总页数 106
  • 原文格式 PDF
  • 正文语种 eng
  • 中图分类
  • 关键词

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