The Scheme Study Of Quantum Secure Direct Communication

The successful development of quantum computer and the further research of quantum information theory have greatly promoted the development of quantum communication technology. Quantum computers have powerful parallel computing capabilities, which is a serious threat to the security of the classical cryptosystem based on computational complexity.Based on the basic principles of quantum mechanics, quantum communication utilizes quantum states as information carrier to achieve encoding, decoding and secure way to transfer information. Quantum secure direct communication is an important branch in the development of quantum communication. In contrast of the quantum key distribution protocol, quantum secure direct communication is able to transmit confidential information directly between two legal parties without pre-sharing a key. However, it is impratical to make both communicating parties legitimate in practice. Therefore, the middle attack exists in quantum secure direct communication schemes potentially. The main content of this thesis is the theoretical study of quantum secure communication with authentication based on EPR pairs and single photons respectively, which is not only to resist the middle attacks effectively, but also to improve the efficiency of communication.The first protocol: high-capacity quantum secure communication with authentication using Einstein–Podolsky–Rosen pairs. In this scheme, the legitimate users pre-share a key between to verify identity. Combinating the operation of classical XOR and auxiliary particles, this protocol enhances the efficiency. This protocol utilizes the entanglement properties of EPR to complete the high-capatity quantum secure communication with authentiention. Due to the difficulties in preparation of quantum entangled states, the implementation of this scheme has some difficulties. Single photons have more pratical value in the current techonogy circumstance, so we propose the second protocol based on single photons.The second protocol: high-capacity quantum secure communication with authentication using single photons. This scheme uses the the ID codes as identification codes and operates XOR on the classic secret information. The results of XOR operation can be distinguished by auxiliary particles. In this way, a single photon can load two classic bits and the scheme achieves high-capacity quantum secure communication with authention using single photons.The thesis analyzes the security of the above two schemes in detail, and existing shemes are used as efficiency comparison. The proposed schemes in the thesis have certain advantages.