Information security risk assessment is a process of comprehensive evaluation of uncertain and random potential risks in order to effectively suppress and transfer systemic risks.On the basis of analyzing the security elements and security system of information system,the information security risk assessment model based on information assets is constructed.Through the risk assessment index system,the attributes of the evaluation objects actually are obtained.The neural network model is constructed by using a set of quantum gate circurit.The normalized processing result of the attribute samples of the evaluation object is used as the network input and expressed by the quantum bit.The phase rotation is performed by the quantum revolving gate and the quenching of the quantum bit is controlled.After being processed by the network,the comprehensive risk of the evaluated object is obtained.The experimental results show that compared with the traditional BP neural network,this method can realize the risk assessment of information systems,with better convergence performance and more accurate risk prediction ability,which can provide a reliable theoretical basis for risk management.

Superconducting quantum computers have the advantages of mature chip processing technology,high system integration,and good scalability.However,superconducting quantum computing needs to increase the quantum integration of chips and ensure decoherence time of quantum chips to achieve fault-tolerant quantum computing.The advancement of superconducting quantum chips is analyzed,and the physical mechanism,advantages and disadvantages of superconducting quantum bus are presented,and several basic quantum bits characteristics are studied.The coupling scheme is discussed between superconducting qubits,including local and non-local coupling.Analysis results on mainstream expansion and layout schemes in recent years show that quantum algorithm programming is suitable for one-dimensional or two-dimensional arrays,while maximum entanglement and full coupling use wraparound expansion schemes to achieve large-scale,high-efficiency quantum to provied an idea for the design of the computational chip.

The research status of quantum communication at home and abroad is discussed.The problem of quantum non-locality and quantum communication complexity is studied.The GHZ problem is solved by entangled particles,and the minimum number of transmitted bits is discussed by using distributed algorithm.The relationship between non-locality and communication complexity is analyzed,and then the simultaneous message passing model is studied.The results show that compared with the classical communication,the quantum communication efficiency is high,and the quantum non-locality problem and the quantum communication complexity problem can be mutually converted.

In view of the lack of effective coding schemes for quantum zero-error channel,based on the characteristics of quantum five-symbol confusion channel model and the theory of matrix theory,a coding method of five-symbol confusion channel combining quantum superposition state zero-error coding is proposed.In order to improve the channel capacity and reduce the algorithm complexity,zero-error coding is performed by using the isomorphism relationship between quantum superposition states and vectors and between channels and matrices.Analysis results show that this method has higher channel capacity and coding efficiency than the classical confusion channel coding method.

In order to reduce the influence of noise on the efficiency of secret information transmission,a quantum steganographic protocol based on Improved Bostrm-Felbinger protocol(IBF) is proposed.The protocol effectively utilizes the characteristics of quantum entanglement and realizes secret information transmission by Controlled non gate(CNOT gate).Among them,the particle embedded with secret information is used as the initial particle of carrier protocol to transmit secret information while executing carrier protocol steps.Analysis results show that the protocol has better anti-noise robustness,concealment and security.

In the future quantum computing era,there will be security risks in the authentication and key exchange links of constructing Virtual Private Network(VPN).Therefore,a VPN enhanced security architecture based on Quantum Secure Key Management Service(QS-KMS) is established to implement quantum security solutions based on quantum cryptography.A global unified backend QS-KMS service is used to provide authentication and session key for IPSec VPN to decouple VPN services from physical layer quantum devices.In view of the complex working conditions and strong environmental interference of power overhead fiber optic cables,the QS-KMS key pool dynamic key management technology and post-quantum cryptography technology are applied to keep the key pool sufficient to ensure the stable operation of VPN.On this basis,the effective quantum security VPN service in the power communication network is realized.Test results show that this method can meet the needs of power grid control communication.

To explore the implementation status of multi-bit quantum algorithm in quantum chips and simulators,Grover search algorithm,quantum random walk algorithm and quantum Fourier transform algorithm are run on IBM quantum chips and simulators respectively.For 2 bit Grover search algorithm and 2 bit quantum random walk algorithm,the influence of measurement times on operation results is analyzed and the maximum number of simulation times is selected to compare the operation results of quantum chip and simulator.A 5 bit quantum Fourier transform algorithm and a 3 bit Grover search algorithm are designed and run,and the IBM Q simulator is used to simulate the maximum number of times respectively.Experimental results show that the quantum chip test results are not optimized with the increase of the number of measurements,and the accuracy of the simulation results is obviously better than that of the quantum chip.

For the one-dimensional Bose-Hubbard theoretical model of condensed matter,the quantum phase transition process of the superfluid-Mott insulation state in the one-dimensional Bose-Hubbard model is realized by continuously changing the depth of the optical lattice well and preparing the temperature of the quantum gas.Through the ultra-cold atomic Time of Flight(TOF) imaging method,the interference pattern of the momentum space of the quantum gas in the diffusion process is analyzed,and the change data of the superfluid component and the Mott insulation state component in the quantum phase transition process are obtained.Experimental results show that the quantum gas in the optical lattice can simulate the one-dimensional Bose-Hubbard theoretical model.