具有细粒度访问控制的隐藏关键词可搜索加密方案

针对现有的可搜索加密算法在多用户环境中密钥管理难度大并且缺乏细粒度访问控制机制的问题，利用基于密文策略的属性加密机制(CP-ABE, ciphertext-policy attribute based encryption)实现了对隐藏关键词可搜索加密方案的细粒度访问控制。数据拥有者可以为其在第三方服务器中存储的加密指定灵活的访问策略，只有自身属性满足该访问策略的用户才有权限对数据进行检索和解密。同时还能够实现对用户的增加与撤销。安全性分析表明方案不仅可以有效地防止隐私数据的泄露，还可以隐藏关键词的信息，使得第三方服务器在提供检索功能的同时无法窃取用户的任何敏感信息。方案的效率分析表明，该系统的检索效率仅为数十微秒，适合在大型应用系统中使用。

Secure hidden keyword searchable encryption schemewith fine-grained and flexible access control

Existing searchable encryption schemes have difficulties in key management for multiple users and could not provide fine-grained access control mechanism. Aiming at solving these problems, a hidden keyword searchable encryp-tion scheme with fine-grained access control was proposed utilizing CP-ABE (ciphertext-policy attribute based encryp-tion) algorithm. Data owners allocate specific and flexible access policy on their data that is stored on a third-party data server. Only those users that has attributes satisfing the access policy are authorized to search encrypted data and decrypt returned results. Moreover, the suggested system has the function to add and revoke user. Security analysis shows that the scheme could not only prevent the leakage of private data but also hide the information of keywords. It deters a third-party storage provider from intercepting users' sensitive information when a search function is provided. The effi-ciency analysis shows that the efficiency of retrieval keeps no more than tens of microsecond and this scheme is suitable for large scale system.