Research On The Practicability Of Quantum Digital Signature

Cryptography has played a very important role in the development of mankind.From classical cryptography,such as Caesar cipher and anticut code,to modern cryptography in the asymmetric RSA algorithm,the application of cryptography in daily life has become more and more extensive,infiltrating into various fields such as economy and military,and bringing extremely high security to the country and people's lives.However,classical cryptography is basically based on the computational complexity of the mathematical puzzles,and cannot give an unbreakable security proof.Moreover,under the in-depth study of quantum algorithms and quantum computers,classical cryptography is facing a great threat.Therefore,with the joint efforts of scholars,a new quantum cryptography has been developed.Like classical cryptography,quantum digital signature is also an important part of quantum cryptography,which not only relies on quantum mechanics to provide unconditional security,but also can ensure the authenticity and integrity of information.This paper first introduces the research background and significance of quantum digital signature and the current situation at home and abroad.Then it briefly described the basic concepts and three theorems of quantum mechanics involved in quantum cryptography,and introduced the unconditional security BB84 protocol,B92 protocol and other quantum key distribution protocols,as well as the classical Gottesman's quantum digital signature,Zeng's arbitration quantum signature protocol.Then,it describes the two protocols proposed in this paper,the practical quantum digital signature against collective noise and the twin-field quantum digital signature protocol based on discrete-phase-randomized sources in detail.The steps and security analysis of each protocol are introduced in detail.Finally,the numerical simulation is carried out on the protocols respectively.The work of the full text is summarized as follows:1.Quantum channels need to be used in the transmission of quantum digital signatures,and quantum channels contain a variety of noises,especially collective noise,which may be used by attackers to cover up eavesdropping.Therefore,in this paper,the decoherence-free-subspace is applied to the signature protocol,and a quantum signature protocol which can resist the collective-dephasing noise and the collective-rotation noise is proposed.The protocol uses the decoherence-free-subspace which can resist the collective noise to generate quantum states.As the carrier of information transmission,the communication fidelity of the protocol can be improved effectively.The protocol only needs to use the same components as quantum key distribution,which is practical.Then,we carry out security analysis and simulation on the protocol performance.The simulation results show that the protocol can resist eavesdropping attacks,such as repudiation attack and forging attack.2.The existing quantum digital signature is limited by the channel key capacity without quantum repeater,so the signature efficiency is relatively low.In order to solve this problem,we propose a twin-field quantum digital signature protocol based on a discrete-phase-randomized sources.The twin-field quantum key distribution method used in this protocol uses discrete-phase-randomized sources in both the test mode and the code mode.Compared with the previous twin-field protocol,the preparation of discrete-phase-randomized sources is simpler and more practical.We have performed security analysis and numerical simulation on the protocol.The simulation results show that,compared with other quantum digital signatures,the secure transmission distance and signature rate of this protocol are improved to some extent.