Reserch Of Quantum Secure Communication Network And Protocol

Quantum secure communication is an important branch of quantum information science. Quantum secure communication which uses the quantum effect to protect the information is based on quantum mechanics and classical cryptography. The security is based on quantum non-cloning theorem and uncertainty principle. Because of the unconditional security of quantum secure communication, it has drawn high attention of every national government and military department. Many researchers and institute are studying the quantum secure communication. Quantum secure communication network becomes the trend to fulfill the requirements of multiple users'secure communications.The contents of this thesis are discussing how to build a quantum secure communication network. Following are the major parts:Discussing the problem of building a quantum secure communication network. The three kinds of QKD network was synopsisly introduced and their advantage and shortage was analyzed. We gave a programming of secure communication system which based on QKD network and classical fiber networks,described its framework and filled all issues into this frame by the subiects they concemed with. And the idea of building wide area network with trust relay node backbone and optical access networks was presented. The bottleneck channel problem of the trust relay node QKD network was put forward,and point out that network coding can significantly raise efficiency and safety of trust relay node QKD network.This paper consider the problem of key distribution between any two users in a quantum secure communication network. A protocol for quantum key distribution between any two users in a network is proposed, it's quantum logical gate scheme is given. The security of the situation that exists an eavesdropper(Eve) is discussed. It is proved that this scheme can withstand the attack effectively.This scheme use only Hadmard gate and CNOT gate, it's easy to be realized in real physical system.A group of orthogonal product state of nolocality is introduced in this paper, and a quantum group key distribution protocol using the product state is proposed. A family of quantum states can be broadcast if and only if the quantum states cummute, so the orthogonal product states is broadcastable.Classical information can be coded on the orthogonal product states, and then broadcast to a group of receiver. The protocol is security under different attack strategy.Product state can be produced and controled easily than entanglment state,the protocol is easy to be realised.