Searchable symmetric encryption (SSE) has been widely applied in the encrypted database for queries in practice. Although SSE is powerful and feature-rich, it is always plagued by information leaks. Some recent attacks point out that forward privacy which disallows leakage from update operations, now becomes a basic requirement for any newly designed SSE schemes. However, the subsequent search operations can still leak a significant amount of information. To further strengthen security, we extend the definition of forward privacy and propose the notion of “forward search privacy”. Intuitively, it requires search operations over newly added documents do not leak any information about past queries. The enhanced security notion poses new challenges to the design of SSE. We address the challenges by developing the hidden pointer technique (HPT) and propose a new SSE scheme called Khons, which satisfies our security notion (with the original forward privacy notion) and is also efficient. We implemented Khons and our experiment results on large dataset (wikipedia) show that it is more efficient than existing SSE schemes with forward privacy.

中文翻译：

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具有前向搜索隐私的可搜索对称加密

可搜索对称加密（SSE）在实践中被广泛应用于加密数据库中的查询。SSE虽然功能强大，功能丰富，但也时常被信息泄露所困扰。最近的一些攻击指出，不允许更新操作泄漏的前向隐私现在成为任何新设计的 SSE 方案的基本要求。但是，后续的搜索操作仍然会泄漏大量信息。为了进一步加强安全性，我们扩展了前向隐私的定义，并提出了“前向搜索隐私”的概念。直观地说，它要求对新添加的文档进行搜索操作，不要泄露有关过去查询的任何信息。增强的安全概念对 SSE 的设计提出了新的挑战。我们通过开发隐藏指针技术 (HPT) 来解决这些挑战，并提出了一种称为 Khons 的新 SSE 方案，它满足我们的安全概念（具有原始的前向隐私概念）并且也是高效的。我们实施了 Khons，我们在大型数据集（维基百科）上的实验结果表明，它比具有前向隐私的现有 SSE 方案更有效。