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arXiv 2309.04697cs.CR
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针对前向与后向隐私可搜索对称加密的泄露滥用攻击

Leakage-Abuse Attacks Against Forward and Backward Private Searchable Symmetric Encryption

Lei Xu, Leqian Zheng, Chengzhi Xu, Xingliang Yuan, Cong Wang

AI总结:

本文揭示了前向与后向隐私DSSE方案在查询相等性和体积信息上的固有泄露缺陷,提出了频率匹配和体积推断两种泄露滥用攻击,呼吁设计新方案以保护查询隐私。

摘要:

动态可搜索对称加密(DSSE)使服务器能够高效地对加密文件进行搜索和更新。为了最小化更新过程中的泄露,新提出的DSSE方案通常期望具备名为前向和后向隐私的安全概念。这些方案通常以打破搜索和更新查询之间针对给定关键词的链接性来构建。然而,前向和后向隐私的DSSE对于实用的泄露滥用攻击(LAAs)是否具有抵抗力,目前仍缺乏深入探索。在这种攻击中,攻击者试图从查询期间被动收集的泄露信息中恢复出查询关键词。在本文中,我们旨在通过两项非平凡的研究首次坚定地回答这一问题。首先,我们回顾了过去几年中前向和后向隐私DSSE方案的发展全貌,并揭示了大多数方案中存在的一些固有构造局限性。这些局限性使得攻击者能够利用查询相等性,并在满射到候选关键词的不同(刷新后的)查询令牌之间建立有保证的链接。其次,我们通过将更新和查询的体积泄露特征与特定操作相关联,对其进行了细化。通过进一步利用更新体积和查询响应体积,我们证明了所有前向和后向隐私的DSSE方案都可能泄露与没有此类安全保证的方案相同的体积信息(例如,插入体积、删除体积)。为了验证我们的发现,我们实现了两种通用的LAAs,即频率匹配攻击和体积推断攻击,并在动态环境下的各种实验设置中对其进行了评估。最后,我们呼吁设计新的高效方案,以在搜索和更新查询中保护查询相等性和体积信息。

英文摘要:

Dynamic searchable symmetric encryption (DSSE) enables a server to efficiently search and update over encrypted files. To minimize the leakage during updates, a security notion named forward and backward privacy is expected for newly proposed DSSE schemes. Those schemes are generally constructed in a way to break the linkability across search and update queries to a given keyword. However, it remains underexplored whether forward and backward private DSSE is resilient against practical leakage-abuse attacks (LAAs), where an attacker attempts to recover query keywords from the leakage passively collected during queries. In this paper, we aim to be the first to answer this question firmly through two non-trivial efforts. First, we revisit the spectrum of forward and backward private DSSE schemes over the past few years, and unveil some inherent constructional limitations in most schemes. Those limitations allow attackers to exploit query equality and establish a guaranteed linkage among different (refreshed) query tokens surjective to a candidate keyword. Second, we refine volumetric leakage profiles of updates and queries by associating each with a specific operation. By further exploiting update volume and query response volume, we demonstrate that all forward and backward private DSSE schemes can leak the same volumetric information (e.g., insertion volume, deletion volume) as those without such security guarantees. To testify our findings, we realize two generic LAAs, i.e., frequency matching attack and volumetric inference attack, and we evaluate them over various experimental settings in the dynamic context. Finally, we call for new efficient schemes to protect query equality and volumetric information across search and update queries.

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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