Analysis And Design Of Quantum Blind Signature Scheme

Digital signature is an important research branch in cryptography.The security of classic digital signature mostly depends on mathematical difficult problem.How-ever,the continuous improvement of the computing power of quantum computers has brought a huge challenge to the security of classic signatures.Therefore,more and more people turn to the research and design of quantum signatures.From the perspectives of the security and feasibility of the quantum blind sig-nature scheme,this paper points out some loopholes and security risks in some quantum blind signature schemes,and also gives some specific improvement mea-sures.Furthermore,we designed a quantum blind signature scheme with higher security.The research contents and main work of this paper are as follows:In the aspect of the analysis of the scheme,this paper conducts a detailed security analysis for two typical quantum proxy blind signature schemes.Through analysis,it is found that there is a forgery attack by verifier in the first scheme.If the verifier is dishonest,he can forge a valid signature according to the signature information he obtained.In another scheme,we find that the scheme could not satisfy the requirements of complete blindness,at the same time,there are also unreasonable assumptions about the arbitrator.In the aspect of the improvement of the scheme,we have improved on two quantum proxy blind signature schemes with some loopholes.In the first scheme,we prevent the verifier's forgery attack by adding an arbitrator.For the other scheme,encryption method is used to make the scheme more blindness,and it also gives more reasonable assumptions to the role of the arbitrator.In addition,for the general quantum proxy blind signature scheme,we also discuss some of the more reasonable security requirements that the scheme should satisfy.In the design of quantum signature scheme,firstly,a model of quantum blind signature for N_j-qubit(3?N_j?6,N_j?N~*,j=1,2,3,4)entangled states based on controlled quantum teleportation is given by us.Then according to the proposed model theory,a novel quantum blind signature scheme based on four-qubit entangled state is presented by us.Different from the traditional schemes,the arbitrator does not have too much authority and information in our scheme,it also does not help the verifier to verify the validity of the signature during the verifying phase.The arbitrator will verify the validity of the signature only in the event of a dispute.I hope our research can play a positive role in the design of quantum blind signatures.