Multi-keyword rank searchable encryption (MRSE) returns the top-$k$k results in response to a data user's request of multi-keyword search over encrypted data, and hence provides an efficient way for preserving data privacy in cloud storage systems while without loss of data usability. Many existing MRSE systems are constructed based on an algorithm which we term as $k$k-nearest neighbor for searchable encryption (KNN-SE). Unfortunately, KNN-SE has a number of shortcomings, which limit its practical applications. In this paper, we propose a new MRSE system which overcomes almost all the defects of the KNN-SE based MRSE systems. Specifically, our new system does not require a predefined keyword set and supports keywords in arbitrary languages, is a multi-user system which supports flexible search authorization and time-controlled revocation, and it achieves better data privacy protection since even the cloud server is not able to tell which documents are the top-$k$k results returned to a data user. We also conduct extensive experiments to demonstrate the efficiency of the new system.

中文翻译：

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任意语言加密数据的多用户多关键字排名搜索

多关键字排名可搜索加密 (MRSE) 返回顶部 -$千$克结果响应数据用户对加密数据进行多关键字搜索的请求，因此提供了一种在不损失数据可用性的情况下保护云存储系统中的数据隐私的有效方法。许多现有的 MRSE 系统是基于我们称为的算法构建的$千$克- 可搜索加密的最近邻居 (KNN-SE)。不幸的是，KNN-SE 有许多缺点，限制了它的实际应用。在本文中，我们提出了一种新的 MRSE 系统，它克服了基于 KNN-SE 的 MRSE 系统的几乎所有缺陷。具体来说，我们的新系统不需要预定义的关键字集，支持任意语言的关键字，是一个多用户系统，支持灵活的搜索授权和时间控制的撤销，即使没有云服务器，它也实现了更好的数据隐私保护。能够分辨哪些文件是最重要的$千$克结果返回给数据用户。我们还进行了大量实验来证明新系统的效率。