中文摘要：

根据MOV归约理论，采用双线性映射构造的基于身份加密方案使得该方案不具有椭圆曲线高效的优点．针对这一点，参考组合公钥体制提出了一种非双线性映射下可证明安全的基于身份加密方案，并且通过采用Katz-Wang的双公钥思想，使得该方案在随机预言机模型下的安全性证明中具有“紧”的归约．为了说明提出方案具有较好的实用性，分析了该方案的归约程度和执行效率．为了使提出方案在具有大量用户的系统中同样具有实用性，提出了多域基本模型．

英文摘要：

According to the MOV reduction theory, the identity-based encryption scheme which is based on the bilinear map will lose the high efficiency of elliptic curve. For this reason, a provably secure identity-based encryption scheme without the bilinear map is proposed, which is based on combined public-key scheme. Furthermore, by applying the pair public-key technology introduced by Katz and Wang, the security proof of the proposed identity-based encryption scheme has ＂tight＂ reduction in the random oracle model. For showing the good efficiency of the proposed identity-based encryption scheme, the degree of reduction in the security proof and the performance of time and space complexity are analyzed, and these terms are compared with other identity-based encryption schemes without the bilinear map. Finally, for overcoming the conspiracy attack of combined public-key scheme, the number of users in the proposed identity-based eneryption scheme is confined, thus leading to the result that the proposed identity-based encryption scheme is inefficient when the number of user is too large. So, for keeping the efficiency of the proposed identity-based encryption scheme in the system having a lot of users, multi-field model in the Kerberos protocol is consulted with, and then a basic multi-field model based on the proposed identity-based encryption scheme is proposed.