一种有效的带关键字搜索的代理重加密方案

带关键字搜索的公钥加密(PEKS)是一种实用的加密范例，它可以在不损害原始数据安全性的情况下搜索加密数据，同时它为解决公钥密码系统中的加密数据检索问题提供了一种有前途的解决方案。作为PEKS和代理重加密(PRE)的组合，带关键字搜索代理重加密允许一个半信任的代理同时重新加密和搜索委托的加密数据。在2010年，Shao等人首先提出了一种基于关键词搜索的代理重加密方案，但其方案的安全性是以降低计算效率为前提的。本文提出一个新的带关键字搜索的代理重加密方案来解决这个问题。与已有的方案相比，本文方案在性能上有明显的提升，使得整个方案除了测试算法外，其他算法都无需使用双线性对运算。本文方案同时满足陷门不可区分和关键字密文不可区分的安全性。对比分析表明，该方案是有效的、实用的。

An Efficient Proxy Re-encryption Scheme with Keyword Search

Public key encryption with keyword search(PEKS) is a practical cryptographic paradigm that enables one to search for the encrypted data without compromising the security of the original data. It provides a promising solution to the encrypted data retrieval issue in public key cryptosystems. As a combination of PEKS and proxy re-encryption(PRE), PRES allows a semi-trusted proxy to simultaneously re-encrypt and search a delegator’s encrypted data. In 2010, Shao et al. firstly presented a proxy re-encryption with keyword search scheme, but their scheme’s security is based on the premise of reducing computing efficiency. This paper solves this problem by presenting a new proxy re-encryption scheme with keyword search without bilinear pairings except the text algorithm. In the random oracle model, it is formally proved that the proposed scheme satisfies the trapdoor indistinguishability security and keyword ciphertext indistinguishability security. Comparison analysis shows that it is efficient and practical.