Improved arbitrated quantum signature scheme using Bell states

We investigate the existing arbitrated quantum signature schemes as well as their cryptanalysis, including intercept-resend attack and denial-of-service attack. By exploring the loopholes of these schemes, the malicious signatory may successfully disavow signed messages, or the receiver may actively negate the signature from the signatory without being detected. By modifying the existing schemes, we develop counter-measures to the attacks using Bell states. The newly proposed scheme puts forward the security of arbitrated quantum signature. Furthermore, several valuable topics are also presented for the further research on quantum signature scheme.