高效无证书签名方案的安全性分析和改进

最近，张玉磊等人提出一个基于双线性对的高效无证书签名方案，通过对其提出的方案进行安全性分析，指出他们的方案对替换公钥攻击是不安全的。对张玉磊等人的方案进行了改进，在q-强Diffie-Hellman困难性假设和离散对数困难假设下，在随机预言机模型中证明改进后的方案，是存在性不可伪造的。

Security analysis and improvement of efficient certificateless signature scheme

Recently,Zhang Yu-lei et al.proposed an efficient certificateless signature scheme based on bilinear parings.By analyzing the security of the Certificateless Signature(CLS)scheme proposed by Zhang et al.,the authors pointed out that their scheme was insecure against public key replacement attack.An improved scheme was proposed.In random oracle model,the improved scheme was existentially unforgeable under q-Strong Diffie-Hellman(q-SDH)assumption and discrete logarithm assumption.