Research On Quantum Signature Protocol Based On Continuous Variable

With the rapid development of information technology,information security plays a pivotal role in all fields of the whole society,which not only concerns the political security,economic security and military security of the country,but also concerns everyone's own interests.Classical cryptography has been playing an important role in information security.However,with the continuous improvement of computer computing power,especially the research of quantum computer,the security of classical cryptographic algorithms based on computational complexity faces great challenges.Quantum cryptography derives from the combination of quantum theory and information theory.Based on the difficulty of large number decomposition and discrete logarithm solution,traditional digital signature can solve the problems of forgery,denial,denial and tampering in network,and effectively guarantee the security of network information.As an important branch of Quantum cryptography,Quantum Signature(QS)is of great significance.After nearly 20 years of research,the quantum signature protocol based on Discrete Variable(DV)has made a lot of achievements.However,the discrete variable quantum signature protocol also has the limitations of single photon,entangled state preparation,photon detection and low communication rate.The quantum signature protocol based on Continuous Variable(CV)has become a research hotspot due to its characteristics of simple quantum state preparation,simple detection and easy laboratory implementation.In order to improve the security and efficiency of Quantum Signature protocol(QS),this paper studies Quantum Signature protocol based on continuous variables,as follows:(1)An arbitrated quantum signature protocol based on quantum dense coding of continuous variables and quantum teleportation is proposed.The scheme has three stages: initialization stage,signature stage and verification stage,which are completed by the signer,the receiver and the mediator.According to the dense coding technique,the signer uses the translation operator to generate the signature of the message on one of the coherent states of the continuous variable entangled state.During the validation phase,the receiver computes fidelity with the help of the mediator.The security analysis shows that the protocol has the characteristics of non-repudiation and non-forgery,especially it can effectively prevent the dishonest receiver from forging signature through an existential attack.Performance analysis shows that in a lossy channel,the mediator can verify the validity of the signature and detect the existence of an attacker by calculating the fidelity parameters.In addition,the channel capacity increases with the increase of transmission efficiency in lossless channels.When the transmission efficiency is greater than 0.681,the channel capacity will be greater than 2,which has a higher communication rate than other existing quantumsignature protocols.(2)A multi-party quantum blind signature protocol based on the graph state of continuous variables is proposed,which enables multiple signers to jointly sign the same message without knowing the content of the message.The scheme has three stages: initialization,signature and verification.In the initialization phase,the sender uses the translation operator to blind the message;in the signature phase,multiple signers use the inverse Fourier transform to complete the signature;in the verification phase,the receiver and the administrator verify the integrity of the message and the validity of the signature respectively.The security analysis shows that the signature of the protocol is non-forgery and non-repudiation,and the signer's blindness to the message is satisfied.The advantage of continuous variable multi-blind signature is that compared with discrete variable multi-blind signature,it has a lower probability of successful forgery.In addition,multi-party quantum blind signature protocol based on continuous variables is easier to be implemented with existing devices.