指定服务器的基于身份加密连接关键字搜索方案

公钥加密关键字搜索(PEKS)允许用户发送关键字陷门给服务器，服务器可以通过陷门定位到包含用户搜索的关键字的密文。为了消除已有基于身份加密的关键字搜索(IBEKS)方案中服务器和接收者之间的安全信道，Wu等人提出了一种指定服务器基于身份加密的关键字搜索(dIBEKS)方案。可是，Wu等人提出的dIBEKS方案不满足密文不可区分性。为了克服Wu等人方案的不足，本文提出一种指定服务器基于身份加密的多关键字搜索方案。安全性分析表明，本文所提方案同时满足了密文不可区分、陷门不可区分和离线关键字猜测攻击的安全性。效率分析显示，本文的方案更高效。

Designated Server Identity-based Encryption with Conjunctive Keyword Search Scheme

Public key encryption with keyword search (PKES) allows a user to send a trapdoor of some searched keywords to a server, which will enable the server locate all encrypted data containing the searched keywords. To remove the secure channel between the server and the receivers in the previous identity-based encryption with keyword search (IBEKS) schemes, Wu et al. proposed a designated server identity-based encryption with keyword search (dIBEKS) scheme. However, Wu et al.’s dIBEKS scheme can not satisfy the ciphertext indistinguishability. To overcome the security weakness in Wu et al.’s scheme and provide the functionality of multiple keywords searching, we put forward a designated server identity-based encryption with conjunctive keywords search scheme. The security analysis shows that the proposed scheme simultaneously satisfies the security of ciphertext indistinguishability, trapdoor indistinguishability and off-line keyword-guessing attack. Comparison analysis shows that the proposed scheme is more efficient and practical.