Abstract: The previous Public key Encryption with Keyword Search（PEKS） framework and Secure Channel Free PEKS（SCF-PEKS） framework inherently suffer from the security vulnerabilities caused by the Keyword Guessing（KG） attack. To address this problem, a new framework called Secure Channel Free PEKS Without Designated Server（SCF-WDS-PEKS） is introduced. The SCF-WDS-PEKS framework has the merits of secure channel freeness and no designated server, while providing resistance to the KG attack. Under this framework, an efficient pairing-based SCF-WDS-PEKS scheme is developed. In the standard model, the proposed scheme is strictly proven to achieve the keyword ciphertext indistinguishability and the keyword trapdoor indistinguishability against adaptive chosen keyword attacks. Compared with some previous PEKS and SCF-PEKS schemes, it not only has the better properties, but also enjoys obvious advantage in both the computation efficiency and the communication cost.

Key words: searchable public key encryption, keyword search, keyword guessing attack, bilinear pairing, standard model

摘要： 已有带关键词搜索的公钥加密方案和无安全信道的带关键词搜索的公钥加密方案存在关键词猜测攻击的安全性缺陷。针对这一问题，提出了一个无安全信道无指定服务器的带关键词搜索的公钥加密方案框架。该框架不仅具有无安全信道和无指定服务器的优点，而且有效解决了关键词猜测攻击的问题。基于该框架，构造了一个高效基于双线性对的无安全信道无指定服务器的带关键词搜索的公钥加密方案，并在标准模型中严格证明了该方案满足适应性选择关键词攻击下的关键词密文不可区分安全性和关键词陷门不可区分安全性。与已有的一些带关键词搜索的公钥加密方案和无安全信道的带关键词搜索的公钥加密方案相对比，该方案不仅具有优良的特性，而且在计算效率和通信代价上具有明显的优势。

关键词: 可搜索公钥加密, 关键词搜索, 关键词猜测攻击, 双线性对, 标准模型