一种可证安全的密钥隔离无证书代理重加密方案

在代理重加密体制里，一个不可信的代理服务器将用Alice公钥加密的密文转换为用Bob公钥加密的密文，同时该代理服务器无法获知明文及相关用户的私钥。无证书代理重加密体制能够同时避免传统公钥基础设施中复杂的公钥证书管理和基于身份加密中的密钥托管问题。考虑到用户私钥泄露可能带来的危害，该文提出了具有密钥隔离功能的无证书代理重加密体制，随机预言机模型中的安全证明和模拟实验表明该方案是高效安全的。同时，设计了基于云计算的移动互联网中的安全数据共享方案。

An Efficient Key-Insulated Proxy Re-Encryption Scheme in Certificateless Cryptography

In a proxy re-encryption scheme, an untrusted proxy can convert the cipher text encrypted by Alice to the cipher text encrypted by Bob. Certificateless proxy re-encryption scheme has the advantages that avoiding the complicated public key infrastructure (PKI) and solving the problem of key-escrow in identity-based cryptography. To deal with the disastrous result of key leakage, a certificateless proxy re-encryption scheme featured with key insulated function has been proposed in this paper. Security proof in the random oracle model and experiment results demonstrate that the proposed scheme is secure and practical. At last, a secure data sharing scheme for cloud-based mobile Internet has also been given based on the proposed encryption scheme.