Security analysis of a signature scheme with message recovery
Tianjie Cao, Dongdai Lin · Journal of Zhejiang University(Science Edition) · 2006
LI and YANG proposed a message recovery signature scheme(LY scheme) based on both the discrete logarithm problem and the factorization problem.WU and LI proved that the security of the LY scheme is only based on the difficulty of factoring.To eliminate this weakness,they also proposed an improved scheme(WL scheme).However,the security of the improved scheme is not as secure as they have claimed.An attacker could generate a forged signature on the assumption when the factorization problem is solved.