Cryptanalysis on quantum digital signature based on asymmetric quantum cryptography

In this paper, we first study the cryptanalysis of quantum signature scheme based asymmetric quantum cryptography. Then the results of analysis show that quantum signature scheme exits the forgery attack. Finally, we give some suggests used to improve the above scheme, for example, a security detection mechanism should be performed in the above schemes. Furthermore, this quantum signature scheme also can withstand the forgery attack by adding a random positive integer shared in between the signer and the verifier.