Paper 2005/062

Cryptanalysis of One Fair E-cash System

LiHua Liu and Zhengjun Cao

Abstract

One fair e-cash system was proposed in [1]. In this paper, we show that the system is insecure. Besides, we point out that there are two drawbacks. One is that those integer intervals for $s_i (i=1, \cdots, 9)$ are unappropriate. The other is that the datum $s_3$ in signature data is redundant. Moreover, we give a minute description of the technique to shun the challenge in the scheme. We think the method is a little interesting.