Research On Controlled Quantum Safety Direct Communication

Quantum information science,a.new field combining quantum mechanics with information science,provides a new approach to the development of information science.Quantum information science,a new field combining quantum mechanics with information science,provides a new approach to the development of information science.Quantum communication is not just an important branch of quantum information science but also is expected to be the first application field of quantum technology.Quantum communication introduces quantum mechanics to traditional communication,Its security is guaranteed by the basic principles of quantum mechanics,Such as the unknown qubit uncloneable,non-orthogonal quantum state can't be identified,quantum state measurement can't be disturbed system etc.,absolutely secure communication.Quantum no-cloning theorem and Heisenberg's uncertainty principle to ensure the unconditional security and the ability of detecting eavesdropper,these facts guarantee that quan,tum cryptography has the excellent capacity and the attractive foreground.In quantum communication technology,quantum channel is very important as the transmission channel,so how to choose the quantum channel is the key point of our research.In order to ensure the validity and correctness of quantum communication and computation,it is an important topic in the research of quantum information.Therefore,in this paper,different quantum states are chosen as transmission channels for different schemes.In this paper,first of all,the theoretical principle and basic form of quantum communication are introduced in this thesis.Secondly,it is that a kind of controlled secure direct communication using quantum entanglement swapping is proposed.Entanglement swapping principle of the basic principle of quantum mechanics is mainly applied and the like-GHZ is used as quantum channel in this scheme.It is has no secret information in the communication process.In order to simplify the communication process,another CQSDC is proposed.In this scheme,the sender can send a secret bit string to the receiver,the receiver can obtain the complete secret bit string only if the controller allows it.In the absence of any secure classical quantum channel.