一种高效的不可否认门限代理签名方案的分析及改进

Yang等人在对Hsu等人的门限代理签名方案进行分析的基础上提出了一种高效的不可否认门限代理签名方案。本文指出Yang等人的方案不具备防伪造性，并提出两种改进方案 ，使其在保证高效性的前提下更加安全。

Cryptanalysis of an Efficient Nonrepudiable Threshold Proxy Signature Scheme

Hsu et al proposed a nonrepudiable threshold proxy signature scheme with known signers,and Yang et al pointed out some weaknesses of the scheme and proposed an improvement scheme with high efficiency.In this paper,we give a cryptanalysis of the Yang et al's scheme.Furthermore,we improve the security of the threshold proxy signature scheme which remedies the weaknesses of the Yang et al's scheme.