基于 ElGamal 体制的无需配对无证书签名方案

摘要

Certificateless cryptosystem became more and more popular because it eliminates the complicated certificates manage-ment in PKI and the keys escrow problem.However,it shows poor efficiency because it based on bilinear pairs.A new certificateless signature scheme without paring is proposed,which based on ElGamal algorithm.The ElGamal algorithm can eliminate the bilinear pairs operation,and then the security proofs of signature scheme has been described by Random Oracles Model.The security vulnera-bility in existing schemes has been avoided in our scheme.Analysis result shows that both the amount of calculation in verification process and the signature length have been reduced by 20 and 33.3 ,respectively,compared with the existing scheme.%基于双线性对的无证书密码系统避免了基于 PKI 密码技术中复杂的证书管理问题，也避免了基于身份密码系统中的密钥托管问题，具有较好的优势而得到了推广。由于双线性对运算比较耗时，因此其计算效率较低。该文基于 ElGam-al 签名体制和无证书密码系统，提出一种 ElGamal 型无需配对的无证书签名方案，有效去除了复杂的双线性对运算，并用随机预言模型证明了其安全性，避免了现有方案中密钥生成时存在的安全漏洞。分析表明，与现有方案相比，新方案在验证阶段计算效率提高了20，其签名长度优化了33．3。