The Study Of High Efficient Quantum Secure Communication

Quantum information,which mainly includes quantum communication and quantum computation,is a new interdisciplinary subject developed rapidly in recent years.Now,with the development of quantum information technology,the traditional cryptographic system that relies on the computational complexity to ensure security has suffered a serious threat,however,quantum communication technology based on the physical characteristics of quantum system provides the possibility to solve this problem.Depending on the basic principles of quantum mechanics and utilizing all kinds of quantum states as carriers,quantum secure communication uses unitary transformation and quantum measurement to achieve the secret messages' encoding,transmission and decoding.Quantum dialogue,which is also called bidirectional quantum secure direct communication,is a very important branch in the development of quantum communication technology.Security and efficiency are two important factors to evaluate the quality of quantum communication protocols,researchers have also been working on high efficiency and high security quantum dialogue protocols.The main content of this paper is the efficient quantum secure communication theory,which is to ensure the security of the communication protocol and improve the communication efficiency.The first scheme: considering the difficulty of preparation and measurement with the entangle photon states,many quantum dialogue protocols use the single photon states that are relatively easy preparation and measurement as the carrier of private information.This paper analyzes and designs the single photon quantum dialogue scheme under researching the singe photon quantum dialogue protocols,then proposes a high efficient quantum dialogue protocol with authentication based on single photons.In this scheme,the two legitimate communicants can detect eavesdropping and authenticate the others' identity by using the pre-shared keys.At the same time,by using different encoding operations,corresponding relationship between the initial states and the final states of the single photons,the two legitimate communicants can enhance the communication efficiency of the protocol on the premise of secret messages' secure transmission.The second scheme: the quantum dialogue protocol in first scheme is only based on the ideal environment,however,in the actual application environment,the impact of noise on quantum communication will not be ignored.At the same time,the paper also considers that add a controller in the communication to supervise the secret messages exchanging.By combining this two conditions,this paper studies and proposes a fault-tolerant controlled quantum dialogue using logical qubit.The paper first proposes a controlled quantum dialogue protocol based on single photons in an ideal environment.This protocol uses single photon states as information carrier and different encoding operations,which can not only overcome the information leakage,but also improve the communication efficiency.Then,by using different logical qubits and unitary transformations,the protocol can fit the collective-dephasing noise,collective-rotation noise and all kinds of unitary collective noise.The protocol is the first time to propose a controlled quantum dialogue in noisy environment,and the unitary operation used in the protocol cannot be discriminated unambiguously with only one opportunity,which ensures the security of the dialogue.In view of the existing attack strategies,the proposed two protocols in this paper make detailed security analysis and proves the security of the two protocols.More importantly,compared with the existing protocols,the efficiencies of the two proposed protocols have certain advantages in terms of the efficiency.