Digital signature schemes based on factoring and discrete logarithms

Wei-Hua He (see Electron. Lett., vol.37, no.4, p.220-22, 2001) proposed a digital signature scheme based on two well-known mathematics hard problem assumptions. The security of the proposed scheme is based on the difficulties of simultaneously solving the factoring and discrete logarithm problems with almost the same sizes of arithmetic moduli. It is shown that He´s scheme is not secure if attackers can solve discrete logarithm problems.