Study On Quantum Secure Direct Communication With Bell State

With the development of information technology,information security is getting more and more important.Quantum communication has the characteristic of unconditional secure transmission,and this technology is widely concerned.As a branch of quantum communication,quantum secure direct communication attracts scholars to study deeply.The main work of this paper is as follows:1.The basic knowledge of quantum mechanics and quantum communication general technologies are introduced.And the classic Ping-Pong protocol and Two-Step quantum secure direct communication protocol are studied in detail.2.The controlled QSDC protocol based on Huffman compression coding is proposed.The original secret information is compressed with Huffman coding to improve communication transmission efficiency.Controller only sends initial state of sequence generator,which makes communication parties to get pseudo-random sequence.Different dense coding rules on parity-data can improve coding capacity.The security and transmission efficiency of the protocol are analyzed with quantum information theory.3.The QSDC protocol based on the mixture of Bell state particles and single photons is proposed.The two eavesdropping detections and sequential rearrangement ensure the security of communication channel and coding sequence.In this protocol complex U operation and entanglement swapping are not used,and implementation process is simplified.Further,the encoding rule that a quantum state encodes with three bits classical message can greatly improve coding capacity.Accordingly,the message transmission efficiency is also improved.Compared with some classic protocols,the protocol has certain superiority.