分析了Chai等提出的利用二次剩余构造的基于身份的签名方案,指出该方案由于使用某些参数,使方案不仅效率低,而且没有有效利用二次剩余。指出方案存在安全问题,给出了两种攻击方法。攻击者可以通过乘法攻击以及构造幂次攻击伪造有效的密钥。为了解决这些问题,提出了改进方案,改进后的方案有效解决了原方案存在的问题。
Analysis of identity-based signature scheme based on quadratic residues proposed by Chai et al is given.Due to using certain parameters,the results show that the scheme not only has the problems of low efficiency,but also doesn't make good use of quadratic residues.They also show that there are security issues in the scheme.Two attacks on the scheme are given.The attacker can forge signing keys by multiplying and constructing powers.In order to solve these problems,the original scheme is improved.The improved scheme solves the problems in the original scheme efficiently.