两个无证书代理环签名方案的攻击与改进

ATTACK AND IMPROVEMENT ON TWO CERTIFICATELESS PROXY RING SIGNATURE SCHEMES

对文献[19]提出的无证书代理环签名方案进行安全性分析,指出该签名方案存在严重的安全问题,即原始签名人的私钥可以被代理签名人恢复出来。指出文献[22]提出的一个标准模型下无证书代理环签名方案也是不安全的,它能够受到两种攻击,即用户从KGC为其生成的部分私钥中可以恢复出系统主密钥、任何用户都可以对任意选择的消息伪造代理签名。分析该方案存在这种攻击的原因,探讨如何克服此类攻击的方法。

This paper analyzed the security of a certificateless proxy ring signature scheme presented by Shi [19],and pointed out a serious security problem in this signature scheme,that was the private key of the original signer could be recovered by the proxy signer.In addition,a certificateless proxy ring signature scheme in the standard model proposed by Zhang et al [22] was also insecure.It could be attacked by two kinds of attacks,that is,the user could recover the system master key from part of the private key that generated by KGC,and any user could forge the proxy signature for arbitrarily selected messages.We analyzed the reasons for this attack and disscussed how to overcome it.