Verifiable Blind Quantum Computing And Its Application To Ensemble Computing Problems

With quantum computers making breakthroughs in computing scale and stability,more and more people are paying attention to quantum power.Blind quantum computing is an important subtopic in the field of quantum information,which allows clients with weak quantum capabilities to delegate their computing problems to quantum servers and keep the input,output and algorithm of the client confidential.It is an effective scheme to solve the difficulty for ordinary people to access quantum computers in the early stage of quantum computing development.Scalability,efficient verification method and low resource consumption are the urgent problems of blind quantum computing.The application of blind quantum computation in secure multi-party computing is an unavoidable topic in its development.Based on this,this paper conducts research on multi-client open verifiable blind quantum computation and quantum private set computation.The main work is as follows.(1)A quantum private set intersection protocol based on Hadamard gates is proposed.In the private set intersection computation protocol based on quantum Fourier transform,semihonest third-party assistance was introduced to make both parties get the calculation results fairly,but privacy disclosure between participants appeared.Through exclusive-OR calculation,participants' private information is randomly selected and encoded in additional n qubits,so that participants cannot obtain the result of difference set,so as to avoid internal disclosure of private information and ensure the security of participants'private information.Hadamard gate is used to replace the quantum Fourier transform of the original protocol,which makes the implementation of the protocol easier.(2)A quantum private set computation protocol based on Hadamard gates is proposed.In view of the fact that verification is not considered in the current research on private set protocols,we improve the quantum private set protocol and propose a verifiable quantum private set computation protocol,which can optionally solve the intersection or union problem.(3)A public verifiable measurement-only blind quantum computation model Based on Entanglement Witnesses is proposed.It allows random legitimate users to detect cheating on both the client and server.In this paper,we propose a publicly verifiable protocol for blind quantum computation with two-color graph state.The fidelity of the graph is estimated by measuring the entangled eyewitness of the graph,so as to verify the correctness of the graph.In the protocol,the duplicate size required for verification is O(n2logn),and the number of local measurements is O(n3logn),which is significantly reduced compared with relevant protocols.(4)A private set computation protocol based on publicly verifiable blind quantum computation model is proposed.For the set computation problem,considering that the multi-party clients may only have weak quantum capability,blind quantum computation model is needed.However,the above publicly verifiable blind quantum computation model only has one client for calculation at a time,so it cannot meet the requirements of multi-party secure computation.In order to apply to set computation,we extend the number of clients participating in the open verifiable model to m-party firstly,and then propose a set computing protocol based on verifiable blind quantum computation,which provides a new idea for secure multi-party computation.