Cryptanalysis of Lee-Chang Group Signature and Its Derivatives
SI Taozhi · Jisuanji gongcheng · 2003
In 1998,Lee and Chang proposed a group signature scheme based on the discrete logarithm problem. Lately Seng-Jan; Li, Zhang, Liu, Yong; and Ao, Chen, Bai give respectively new improved schemes based on Lee-Chang scheme. This paper shows that these schemes derived from Lee-Chang are not secure and untraceable group signatures are given by similar forery attacks.