中文摘要：

针对已有基于证书代理重加密（PRE）方案需要复杂的双线性对运算,计算效率较低的问题,提出了一个高效的不依赖于双线性对的基于证书代理重加密方案。基于计算性Diffie-Hellman（CDH）问题的困难性假设,该方案在随机预言模型下被严格证明满足适应性选择密文攻击下的不可区分安全性,即满足选择密文安全性。所提方案的构造基于椭圆曲线群,避免了计算开销高昂的双线性对运算,因此方案的计算性能得到了显著提高。对比分析表明,相对于已有使用双线性对的基于证书代理重加密方案,所提方案在计算效率和通信代价两个方面都具有明显的优势,更适用于计算受限以及低通信带宽的应用场合。

英文摘要：

All the previous certificate-based Proxy Re-Encryption（ PRE） schemes are based on the computationallyheavy bilinear pairings,and thus have low computation efficiency. To solve this problem,a certificate-based proxy reencryption scheme without relying on the bilinear pairings was proposed over the elliptic curve group. Under the hardness assumption of the Computational Diffie-Hellman（ CDH） problem, the proposed scheme was formally proven to be indistinguishable against adaptively chosen-ciphertext attacks in the random oracle model. Due to avoiding the time-consuming bilinear pairing operations,the proposed scheme significantly reduced the computation cost. Compared with the previous certificate-based proxy re-encryption schemes with bilinear pairings,the analysis shows that the proposed scheme has obvious advantages in both the computation efficiency and the communication cost, and the scheme is more suitable for the computation-constrained and bandwidth-limited applications.