中文摘要：

基于量子信道加密原理，结合Ping．Pong协议控制模式和信息模式的概念，提出了一个量子安全直接通信协议。在此协议中，发送者和接收者用n对Bell态作为量子信道，发送者用controlled．Not操作将单粒子纠缠入量子信道，接收者用controlled—Not操作将单粒子与量子信道解纠缠。通信双方依次执行控制模式和信息模式，控制模式检测窃听，信息模式发送秘密信息。控制模式和信息模式均不会对已建立的量子信道造成破坏，因此建立量子信道的过程仅需执行一次，此后通信双方可以反复进行控制模式和信息模式，从而不断进行窃听检测和秘密信息传输。

英文摘要：

Based on quantum encryption and Ping-Pong protocol, a quantum secure direct communicationprotocol was proposed. In this protocol, sender and receiver used n pairs Bell states as carrier, senderentangled single particle in carriers by performing controlled-Not operations and receiver disentangled singleparticle in carriers also by performing controlled-Not operations. Communication partners performed controlmode and message mode in turn. Control mode detects eavesdropping and massage mode sends secretmessage. Control and message mode did not break Bell states so the process of sharing Bell states wasone-time, then communication partners can execute control and message mode again and again to detecteavesdropping and send secret