Security Analysis of Liu-Zhang-Deng Digital Signature Scheme

In 2010, Liu et al. 1 proposed an improvement of Liu-Li digital signature scheme without one-way hash function and messageredundancy. In this paper, we demonstrate that Liu et al.’s scheme exist ℓ-wDH problem. Using Baby-Step Giant Step, we cancompute (mod p − 1) in o polynomial time, it is therefore insecure and can not against forgery attack.