门限代理重加密.PDF

门限代理重加密 1 2 3 周德华 ，陈克非 , 郑东 1 暨南大学计算机科学系，广州　邮编510632 2 上海交通大学计算机科学系，上海　邮编 200240 3 上海交通大学信息安全工程学院，上海，邮编 200240 摘要：在代理加密方案 (PRE) 中，半可信的代理在不知道明文的情况下将委托人的密文转化 为接收者能解密的密文。它被应用于需要委托的进程中，比如委托分布式文件系统等等。但 是，当半可信的代理机构不再可信时，密文可能会被破解。因此在一些应用中需要委托人有更 大的掌控权利。例如，只有k个满足委托人的门限要求的代理服务器可执行转化和合并操作， 才可以被接收人解密。我们引入门限代理重加密的概念，提出一种相应的方案，并证明了它在 随机预言机模型下的安全性。 关键词：门限代理重加密，双线性映射，选择密文攻击，随机预言机模型 中图分类号：TP309.7 Threshold proxy re-encryption 1 2 3 ZHOU De-Hua , CHEN Ke-fei , ZHENG Dong 1 Department of Computer Science, Jinan University, Guangzhou 510632 2 Department of Computer Science and Engineering, Shanghai Jiao Tong University, Shanghai 200240 3 School of Information Security Engineering, Shanghai Jiao Tong University, Shanghai 200240 Abstract: In a Proxy Encryption (PRE) scheme, a semi-trusted proxy, converts a ciphertext for Alice(delegator) into a ciphertext for Bob(delegatee) without knowing the underlying plaintext. PRE can used for applications requiring delegation, such as delegated distributed file systems, outsourced filtering of encrypted spam, and encrypted email forwarding, etc. However, when the semi-trusted proxy was corrupt and colluded the delegatee, the ciphertext can be decrypted. In some scenarios require the delegator further control the proxy re-encryption. For example, whereby only k proxy servers satisfying the threshold value set by delegator can be transformed and combined, then can be decrypted by delegatee, we introduce the notion of Threshold Proxy Re-Encryption (or TPRE), We