庞晓琼 严小龙 陈文俊 余本国 聂梦飞

摘 要：针对云存储环境下已有的动态多关键词密文排序检索方案不支持关键词语义扩展、不具备前向安全和后向安全的问题，提出一种支持语义检索且具备前向安全和后向安全的动态多关键词密文排序检索方案。该方案通过构建语义关系图实现查询关键词的语义扩展;使用树索引结构实现数据的检索和动态更新;利用向量空间模型实现多关键词排序搜索;基于安全K近邻算法对维度扩展后的索引和查询向量进行加密。安全性分析表明，该方案在已知密文模型下是安全的且具有动态更新时的前向安全和后向安全。效率分析及仿真实验结果表明，该方案在服务器检索效率方面优于目前同类型具有相同安全性或相同功能的方案。

关键词： 对称可搜索加密;多关键词排序检索;动态更新;语义扩展

中图分类号：TP309

文献标志码：A

文章编号：1001-9081（2019）04-1059-07

Abstract： Since existing dynamic multi-keyword ranked search schemes over encrypted data in cloud storage can not support semantic extension and do not have forward and backward security， a multi-keyword ranked search scheme over encrypted cloud data was proposed， which supported semantic search and achieved forward and backward security. The semantic extension of query keywords was achieved by constructing semantic relationship graph， the retrieval and dynamic update of data were achieved by use of tree-based index structure， the multi-keyword ranked search was achieved based on vector space model， and the extended index and query vectors were encrypted by using secure K-nearest neighbor algorithm. Security analysis indicates that the proposed scheme is secure under the known ciphertext model and achieves forward and backward security during dynamic update. Efficiency analysis and simulation experiments show that this scheme is superior to the same type schemes with the same security or function in server retrieval efficiency.

Key words： symmetric searchable encryption; multi-keyword ranked search; dynamic update; semantic extension

0 引言

隨着云计算的迅速发展，用户开始将数据迁移到云服务器，以避免繁琐的本地数据管理同时获得更加便捷的服务[1]，但近年来频繁发生的用户数据隐私泄露问题使得云安全问题受到人们的广泛关注。为保护敏感数据的隐私性，许多用户选择将数据以密文形式存储在云端[2]。但是，数据加密使得传统的明文关键词检索机制失效，如何对密文数据进行高效安全的检索成为亟待解决的问题。可搜索加密技术就是为了解决密文检索难题而……