Improvement of a nonrepudiable threshold proxy signature scheme
一种不可否认门限代理签名方案的改进

Based on security analysis on Hsu' scheme,an improved threshold proxy signature scheme was proposed,which effectively overcomed the disadvantage of Hsu' scheme which couldn't stand the internal conspiracy attack and the forge attack.The improved scheme involved the secret information of both the actual signature group and the proxy signature group into the proxy signature in the proxy signature generation stage,and differed in the signature,so the signature based on it is identifiable and nonrepudiable.Cryptoanalysis on the new improved scheme shows that it is a safe and practicable one.