Abstract: Through analysis of a certificateless aggregate signature scheme proposed by Hou et al, it is revealed that the scheme is not secure and it cannot resist the type two adversary attack. Based on this scheme, an improved certificateless aggregate signature scheme is proposed in this paper. Under the computational Diffie-Hellman problem, it is proved that the new scheme is secure against existential forgery attack in the random oracle model. The result indicates that the new scheme only needs three pairing computations and n scalar multiplication computations in verification phase. The new scheme is more efficient and secure than existed schemes.

Key words: aggregate signature, certificateless cryptography, bilinear pairing, Diffie-Hellman assumption

摘要： 对侯红霞等人提出的无证书聚合签名方案进行分析，指出该方案是不安全的，无法抵抗第二种类型敌手的攻击，并对该方案进行改进，提出了一个新的无证书聚合签名方案，利用Diffie-Hellman困难问题，在随机预言模型下证明了新方案是存在性不可伪造的。效率分析表明，新方案在签名验证中只需要3个对运算和[n]个标量乘运算，比已有方案效率更高更安全。

关键词: 聚合签名, 无证书密码体制, 双线性对, Diffie-Hellman困难问题