A New Digital Signature Scheme without One-Way Hash Functions and Message Redundancy

In 2004, Chang et al. proposed a signature scheme without employing one-way hash functions and message redundancy schemes. Later, Zhang and Fu et al., presented the forgery attack on Chang´s digital signature and claimed that message redundancy schemes should still be used to resist some attacks. In this letter, we will point out a fatal flaw of Chang´s scheme and propose a new digital signature scheme, where neither one-way hash functions nor message redundancy schemes are used