Research On Reference Frame Independent Quantum Digital Signature Protocol

Digital signature plays an important role in modern cryptographic communication.It is widely used in remote communication such as electronic contract and email.The main role is to ensure the integrity of the message and verify the authenticity of the sender’s identity.For classical digital signatures,algorithms based on computational complexity such as RSA,DSA(Digital Signature Algorithm),and ECDSA(Elliptic Curve Digital Signature Algorithm)are usually used to generate keys.However,with the improvement of software and hardware and the rapid development of quantum computers,the security of classical digital signatures is threatened.Therefore,quantum digital signatures(QDS)have been proposed to deal with new threats.The security of quantum digital signatures is guaranteed by the laws of quantum mechanics,and theoretically has unconditional security.Now,the quantum digital signature of the BB84 protocol is the most widely used.Although the quantum digital signature protocol is relatively mature in theory and experiment,in practical application,there may exists some problems such as slow drifts between the reference frames of the two communication parties,state preparation errors and intensity fluctuations at the light source side.The above practical factors may reduce the security of the actual quantum digital signature system,thereby affecting the performance of the system.In view of the above problems,this paper mainly carries out the following research work:1.Most of the existing quantum digital signature protocols have made certain assumptions.For example,it is assumed that the reference frame of both parties in the communication are always consistent,but in fact,the drift of the reference frame will cause the reference frame of the two parties to be inconsistent,which will influence the system performance.In this paper,a reference frame independent quantum digital signature protocol is proposed.In this protocol,the reference frame drift problem is solved by introducing the reference frame independent key distribution protocol into the key generation process of the quantum digital signature.The research results show that the signature rate and transmission distance of the new protocol are better than the previous BB84 protocol when there drifts between the reference frames.2.In view of the non-negligible state preparation error at the source side,we combine the losstolerant method with the reference-frame-independent quantum digital signature protocol,and propose a loss-tolerant quantum digital signature protocol.The protocol only needs to prepare four states,and allows for state preparation errors,which not only decreases the security vulnerabilities of quantum digital signatures,but also reduces the difficulty of experiments.Through mathematical modeling and theoretical analysis,we prove that the loss-tolerant quantum digital signature protocol can well reduce the influence of state preparation errors on the signature rate.