Improved group signature scheme based on Chinese remainder theorem

The group signature scheme based on Chinese remainder theorem proposed by Chen Zewen et al. has been studied, and the design flaw in the signature generation algorithm in Chen's scheme is presented. Furthermore, Li Jun's scheme on the strong RSA assumption based on Chinese remainder theorem has been analyzed. The analysis reveals its vulnerability to joint attack or forgery attack. Thus, according to the digital signature algorithm (DSA), an improved scheme based on Chinese remainder theorem is proposed. The group member can be added or revoked efficiently and effectively without changing the other group member's secret key. Analyses show that the improved scheme can resist joint attack, replay attack, forgery attack and trap attack. In addition, the improved scheme offers a means to optimize the group signature to speed up the calculation by pre-calculating some signature parameters.