【作者】 李婷；

【导师】 郭丽峰；

【作者基本信息】 山西大学 ， 计算机应用技术， 2017， 硕士

【摘要】 代理重加密是指由委派者生成关于受委托者的代理重加密密钥,然后将该代理重加密密钥发送给代理人,代理人使用代理重加密密钥将委派者公钥下的密文转换成受委托者公钥下的密文。代理重加密有着非常广泛的应用前景,例如分布式加密文件系统,加密邮件转发,安全云存储以及数字版权保护等。本文进行两方面的研究:提出了两个关于代理重加密的改进方案。其一,本论文通过对一个带关键字搜索的代理重加密方案中的陷门漏洞进行修复而得到一个改进的带关键字搜索的代理重加密方案,所改进的方案具有陷门可以在公开信道下进行传输,且在标准模型下抵制适应性选择密文攻击下是证明安全的;其二,本论文提出一个简化的完全安全的基于身份的单向代理重加密方案,该方案是通过对Lou等人的方案进行分析研究,发现原方案中存在参数冗余,因此对原方案中的参数进行简化而获得的,它具有与原方案相同的安全性,都是标准模型下完全安全的,但其参数更少更短,因此比原方案的效率更高。更多还原

【Abstract】 Proxy re-encryption is defined as client generates mandatary’s Proxy re-encryption key,then sent the proxy re-encryption key to agent,thus agent u ses the proxy re-encryption key to convert the public key into the ciphertext of consignor.Proxy re-encryption is widely used in many situations,such as distributed file system,mail forwarding,secure cloud storage and digital cop yright protection etc.In this paper,two aspects are studied: the paper puts for ward an improved scheme for proxy re-encryption.Firstly,we propose an i mproved proxy re-encryption scheme with keyword search by repairing a tra pdoor in the proxy re-encryption scheme with keyword search.The improve d scheme has a trapdoor which can be transmitted in the open channel,and it is proved to be safe under the standard model;Secondly,we propose a simp lified and secure identity-based one-way proxy re-encryption scheme based on the analysis of Lou et al,which found that the original scheme was redun dant.Thus,the parameters simplified in the original scheme has the same se curity as the original scheme,and completely safe under the standard model.For its parameters are shorter,it is more efficient than the original scheme.更多还原