The Research Of Quantum Identity Authentication And Secure Direct Communication

Quantum communication has the advantages of higher security and capacity. It has become one of the most important parts of quantum information. Differing from the classical communication, it transmits and processes information based on the principles of quantum mechanics. Quantum communication provides a new way for securely transmitting message. Many scholars in research institutes take part in studying this field. This paper mainly focuses on quantum identity authentication and quantum secure direct communication. Main works are summarized as follow:1. A quantum identity authentication scheme based on chaos is proposed. The extreme sensitivity to initial conditions and parameters of chaotic system and good pseudo-randomness of chaotic sequence are applied to quantum identity authentication. In order to solve the chaotic iterative asynchronous problem, principle of quantum teleportation is used in the scheme. The scheme realizes the "one-time pad" authentication. Finally, the security and feasibility of the scheme are analyzed and discussed.2. Based on the character of three-particle GHZ-state, a scheme of quantum secure direct communication in star network is presented. Any two users in the star network can safely transmit two bits of classical information, through doing different unitary transformation on the particles of GHZ-state. And the scheme has high communication efficiency. Finally, the security of the scheme is analyzed and discussed on the condition that the eavesdropper takes active and passive attacks on the scheme.3. A quantum dense coding scheme in non-symmetric channel is proposed by using a class of three-particle W-state. From the coding results, it can be encoded log218bits of classical information by doing different unitary transformation on two qubits of three-dimensional Hilbert space, which realized superdense coding. Similarly, the dimensions of sender’s and receiver’s particles are extended. And then, based on the method of superdense coding, a quantum secure direct communication scheme is raised. In the implementation of the scheme, the entanglement correlation between particles of W-states is exploited to ensure the security of particle-distribution phase; inserting decoy photons into particles and rearranging the order of particles are used to ensure the security in the information transfer phase. From the final analysis, the scheme not only has higher communication efficiency but also makes information more secure.