Abstract: Wu and Shen point out that there is a weakness in the proxy multi-signature scheme based on elliptic curves discrete logarithm problem proposed by Ji and Li-using forgery attack，anyone of original signers can produce a valid proxy multi-signature.And based on it，a new modified and secure proxy multi-signature scheme is proposed by Wu and Shen.But it still unsafe，if several members collude together，they can make the agent-signature of signing some messages incorrect，because the proxy signature can be look as the proxy signature signed by proxy signer with some of the original signers.At the same time，honest members cannot detect this security flaw in the system，since the group can generate multisignature according to the prescribed protocols.So，a new proxy multi-signature scheme based on Chevbyshev is proposed.

摘要： 基于椭圆曲线离散对数问题的代理多签名体制，Wu和Shen指出了此方案存在的缺点：任何一个原始签名人利用前次有效的代理签名可以伪造出一个有效的代理多重数字签名。为了克服这一缺点，Wu和Shen对这个代理多签名体制的签名认证部分提出了一种改进方案。给出一种攻击方法以表明该改进代理多签名方案仍然是不安全的。在这一攻击中，部分原始签名成员在生成密钥时合谋作弊，就能引发代理人所生成的代理签名违反代理多签名的安全特性规定，从而达到推翻代理签名的目的。与此同时，其他成员仍可正常地产生签名，所以他们觉察不到欺诈的存在。针对此，提出了一种新的基于Chebyshev多项式序列的代理多签名方案。