Research On The Key Issues In Multi-User Quantum Netwrok Secure Communications

With the rapid development of quantum information technology,the establishment of a global quantum network is an inevitable trend in the future,and the foremost application of quantum networks is the quantum communication networks used for transmitting quantum information.Nowadays,due to the merits of high confidentiality,large capacity and fast information processing speed,quantum network communication has attracted the worldwide concerns and researches.However,in the process of quantum network communication,quantum information transmission is susceptible to the channel decoherence,network transmission congestion,malicious attacks and so on,which seriously hinder the practical application of large-scale quantum communication networks.Therefore,in order to promote the practical and large-scale application of quantum network communication,it is of great significance to theoretically study the reliable,efficient and secure multi-user quantum network communications,which has already become a major topic concerned by the scholars.Quantum teleportation and quantum network coding are two important theoretical techniques in quantum network communication.Based on them,this paper studies two key issues in multi-user quantum network secure communication,namely multi-user quantum wireless network communication based on quantum teleportation and quantum multi-unicast network communication based on quantum network coding.Focus on these two issues,reliable,efficient and secure multi-user quantum network communication schemes are designed,which lay the theoretical foundations for the practical application of quantum network communication.Specifically,the main research results and innovations of this paper are summarized as follows:(1)The problems of high computational complexity and low communication efficiency in existing multi-user quantum wireless network communication schemes are analyzed.And to provide lower computational complexity,higher communication efficiency and security,a novel multi-user quantum wireless network communication protocol based on multi?qubit GHZ state and teleportation is proposed.On the one hand,in the theoretical scheme,the quantum wireless network communication is successfully realized through sharing a multi-qubit GHZ state among all nodes involved,and designing appropriate quantum measurements and operations.Owing to the simpler algorithm and the fewer amount of the classical information required to be calculated,the computational complexity of our scheme is less than that of the existing scheme.Moreover,since the consumptions of quantum resource and classical communication,together with the classical communication delay have been reduced,our scheme presents the higher network communication efficiency than the existing scheme.On the other hand,in an actual implementation,a flexible bilayer quantum wireless network architecture and the corresponding secure network communication protocol are proposed.Thus,the network coverage range can be freely enlarged,and the network capacity is also enhanced.These ultimately ensure the reliable,efficient and secure transmission of quantum information through the actual quantum wireless network.(2)Aiming at the problem of quantum information transmission congestion inevitably occured in quantum network communication,a quantum network coding scheme assisted by auxiliary pre-shared entanglement and classical communication is proposed.It can successfully realize the reliable and efficient transmission of quantum information in quantum multi-unicast network.On the one hand,in the theoretical scheme,the required encoding and decoding operations are constructed by the correlated quantum operations and measurements over d-level Hilbert space.Then,by designing the corresponding encoding and decoding processes at each network node with assistance of pre-shared entanglement and classical communication,an efficient quantum network coding scheme is proposed.Compared with the existing schemes,in our scheme,the amount of auxiliary resources is reduced and the 1-max flow quantum communication of value k can be obtained.Thus our scheme presents the higher network communication efficiency and network throughput.On the other hand,in an actual implementation,the performance of our scheme when Pauli errors happened in the pre-shared entanglement resource is analyzed.It is shown that our scheme has good robustness against noises:it can always resist Z error,and when the error parameterp is small enough,it can also resistXerror and the general Pauli error.In addition,the classical communication involved in our scheme will not cause additional network congestions,thereby reducing the communication complexity and providing better adaptability to the large-scale quantum network communications.(3)In order to resist the pollution attacks that seriously threaten the implementation of quantum network coding,a secure quantum network coding scheme based on quantum homomorphic message authentication is proposed.Thus,the reliable,efficient and secure quantum multi-unicast network communication is ultimately realized.Firstly,the concept of quantum homomorphic message authentication is proposed for the first time,and the basic scheme and enhanced scheme of quantum homomorphic message authentication based on quantum circuit are designed to resist the the pollution attacks occur in quantum communication networks.Among them,the enhanced quantum homomorphic message authentication scheme can effectively resist the currently known types of pollution attacks,including external attacks and internal untrusted node attacks.Secondly,combining the enhanced quantum homomorphic message authentication scheme with the quantum network coding scheme,a secure and efficient quantum network coding scheme is proposed.In terms of the security,our scheme can effectively resist the presently known types of pollution attacks that may happen in the process of quantum network communications.In terms of the communication efficiency,our scheme not only can be utilized to solve the problem of quantum information transmission congestion,but also has a significantly higher achievable rate region than the exisiting secure schemes.