门限代理门限签名方案的密码学分析

摘要

Recently,Hwang et al.proposed a(t,n)threshold-proxy(c,m)threshold signature schemes,in which only any t or more original signers of n original signers can authorize a proxy group of m proxy signers and then only c or more proxy signers can co operatively generate threshold-proxy threshold-signature.In this scheme,they claimed that original signers cannot forge the proxy signature and the proxy signers cannot forge signature on behalf of the original signers.However,in this paper,we will give a attack to show that their scheme can not resist impersonation attacks.