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arXiv 2102.09651cs.CR
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可搜索加密中的混淆访问和搜索模式

Obfuscated Access and Search Patterns in Searchable Encryption

Zhiwei Shang, Simon Oya, Andreas Peter, Florian Kerschbaum

摘要:

可搜索对称加密(SSE)允许数据所有者将其加密数据安全地外包给云服务器,同时保持搜索和检索匹配文档的能力。大多数现有的SSE方案泄漏了每个查询访问哪些文档,即,所谓的访问模式,因此容易受到可以恢复数据库或查询关键字的攻击。当前完全隐藏访问模式的技术,例如ORAM或PIR,遭受沉重的通信或计算成本,并且没有考虑到搜索能力而设计。最近,Chen等人(INFOCOM'18)提出了一种用于SSE的混淆框架,该框架以具有合理效用成本的差异私有方式保护访问模式。然而,该方案泄漏了所谓的搜索模式,即,某个查询被执行了多少次。这种泄漏使得该提案容易受到某些数据库和查询恢复攻击。在本文中,我们提出了OSSE(混淆SSE),一个SSE计划,混淆的访问模式独立执行的每个查询。这反过来又隐藏了搜索模式,并使我们的计划抵抗依赖于此泄漏的攻击。在一定的合理假设下,我们的方案具有较小的通信开销比基于SRAM的SSE。此外,我们的计划在一个单一的通信轮,需要非常小的恒定的客户端存储。我们的实证评估表明,OSSE是非常有效的保护不同的查询恢复攻击,同时保持合理的实用水平。我们的协议提供了显着更多的保护比陈等人的建议。针对一些国家的最先进的攻击,这表明隐藏的搜索模式在设计有效的隐私保护SSE方案的重要性。

英文摘要:

Searchable Symmetric Encryption (SSE) allows a data owner to securely outsource its encrypted data to a cloud server while maintaining the ability to search over it and retrieve matched documents. Most existing SSE schemes leak which documents are accessed per query, i.e., the so-called access pattern, and thus are vulnerable to attacks that can recover the database or the queried keywords. Current techniques that fully hide access patterns, such as ORAM or PIR, suffer from heavy communication or computational costs, and are not designed with search capabilities in mind. Recently, Chen et al. (INFOCOM'18) proposed an obfuscation framework for SSE that protects the access pattern in a differentially private way with a reasonable utility cost. However, this scheme leaks the so-called search pattern, i.e., how many times a certain query is performed. This leakage makes the proposal vulnerable to certain database and query recovery attacks. In this paper, we propose OSSE (Obfuscated SSE), an SSE scheme that obfuscates the access pattern independently for each query performed. This in turn hides the search pattern and makes our scheme resistant against attacks that rely on this leakage. Under certain reasonable assumptions, our scheme has smaller communication overhead than ORAM-based SSE. Furthermore, our scheme works in a single communication round and requires very small constant client-side storage. Our empirical evaluation shows that OSSE is highly effective at protecting against different query recovery attacks while keeping a reasonable utility level. Our protocol provides significantly more protection than the proposal by Chen et al.~against some state-of-the-art attacks, which demonstrates the importance of hiding search patterns in designing effective privacy-preserving SSE schemes.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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