带关键词搜索的公钥加密方案的设计与安全性分析研究

Cloud Computing can provide an economic and efficient service for users, but the data privacy in the cloud is the bottleneck of the extensive promotion of Cloud Computing. Encryption is an effective approach to protect the data privacy, while searching over the encrypted data turns out to be extremely difficult. Searching over Encrypted Data is a research hotspot of the information security field, which can achieve the problem of searching in the untrusted model, and will surely promote the development of Cloud Computing. Our project will explore Public Key Encryption with Keyword Search (PEKS), also known as searchable encryption, mainly involves as follows, 1.the design and security analysis of the searchable encryption schemes,2.the reduction between searchable encryption schemes and other cryptographic systems. We will provide a general design of searchable encryption based on attribute-based encryption system, provide a concrete construction of multi-user search scheme over the encrypted data presented by third-party. We will propose a novel searchable encryption scheme that encrypted data presented by the server, which can enhance the efficiency and keep the security at least as same as the existing schemes. We will provide a searchable encryption scheme based on fully simulatable Oblivious Transfer Protocol. We attempt to design PEKS scheme which is security under standard model and prove it.We also try to make the qualitative conclusion on the relation between the searchable encryption scheme and the encryption systems which it based on.

云计算可为用户提供经济快捷的服务，但云中的数据安全却是云计算大规模推广的瓶颈；加密是保护数据机密性的有效手段，然而对加密后的数据进行检索却是一项艰难的工作。加密信息搜索可解决非可信环境下的加密数据检索，是信息安全领域的研究热点，必将对云计算的发展起到重大作用。本项目将对公钥加密搜索（PEKS）方案展开研究，主要包括：1.加密搜索方案的设计与安全性分析；提出基于属性加密的加密搜索方案的一般构造方法；给出具体的对第三方加密数据搜索模型中多用户搜索方案的构造；提出对服务器提供加密数据时搜索方案的构造，在不降低原有此类协议安全性的前提下提高运行效率；给出基于全模拟安全的不经意传输协议的加密搜索方案；给出标准模型下加密搜索方案的构造和安全性证明。2.加密搜索方案与其它密码体制之间的归约关系，对加密搜索方案与它所基于的加密体制之间的关系给出定性的结论。

可搜索加密是云计算安全中最重要的研究方向之一。而公钥可搜索加密是加密搜索领域的重要分支，国内外对这类问题的研究很重视。我们针对公钥可搜索加密相关问题进行了深入研究。首先我们对非指定用户的关键词可搜索加密协议、多关键词公钥可搜索加密协议、模糊关键词公钥可搜索加密协议进行了研究，取得了一系列研究成果，包括基于属性的可搜索加密协议、分级多关键词公钥可搜索加密协议、基于函数保密的属性加密的可搜索加密协议、无记忆模糊关键词公钥可搜索加密协议等等；利用公钥可搜索加密实现了生物认证上的应用，构造出了一个具体的安全认证协议。在对公钥可搜索加密的研究过程中我们还对安全多方计算、签密、基于格的密码学、密钥管理等相关内容做了一些研究，并取得了一些成果。通过我们的探索研究，澄清了一些公钥可搜索加密概念上的东西，大大提高了公钥可搜索加密的灵活性、实用性，为公钥可搜索加密的研究做出了我们的贡献。