指定使用者的多服务器多关键字可搜索加密方案

针对现有可搜索加密方案中密文检索效率低、搜索结果不精确以及不支持数据使用者身份验证等问题，在无证书密码体制下，提出一种指定使用者且多服务器多关键字的可搜索加密方案。使用多服务器和多关键字技术在降低服务器负荷的同时提高用户检索密文的速度，使搜索结果更加精确。在搜索验证阶段，搜索服务器验证数据使用者的身份，若身份合法则存储服务器根据关键字向数据使用者返回相应密文。性能分析结果表明，在随机预言机模型下该方案可以抵抗内外关键字猜测攻击，且能够在降低计算开销的同时提高搜索效率，在安全性和效率方面均具备一定优势。

Multi-Server Multi-Keyword Searchable Encryption Scheme for Designated User

The existing searchable encryption schemes are limited in the efficiency of ciphertext retrieval and accuracy of search results,and generally do not support the verification of data user identity.To address the problems,a multi-server multi-keyword searchable encryption scheme for designated user is proposed under the certificateless cryptosystem.The scheme uses multi-server and multi-keyword technology to reduce the server load and improve the speed of users in retrieving cipher texts,making the search results more accurate.In the search verification phase,the search server verifies the identity of the data user.If the identity is legal,the storage server returns the cipher text corresponding to the keyword to the data user.The performance analysis results show that,under the random oracle model,the scheme can resist the inside and outside keyword guessing attacks,and can reduce the computational cost and improve the search efficiency,exhibiting advantages in both security and efficiency.