基于三粒子纠缠态的量子安全直接通信协议

提出了一种新的三粒子量子安全直接通信协议。通信过程利用decoy光子来检测窃听，保证信道安全。发送方将秘密消息编码在不同幺正操作上，通信双方通过Bell基和Z基测量可直接传递秘密消息。由于所有粒子都用于传输秘密消息，且传输一次可获得两比特信息，该协议具有较高的量子比特及量子密码协议效率；三粒子纠缠态的制备是已实现技术，该协议具有实际操作的意义。此外，该协议在量子信道中也是安全的。

Quantum Security Direct Communication Protocol Based on Three-Particle Entangled State

We present a new quantum security direct communication protocol based on three- particle entangled state. The communication parties utilize decoy photons to check eaves- dropping. The sender encodes the secret message with unitary transformation, we can di- rectly transmit secret message with Bell-basis measurement and Z-basis measurement. The protocol is efficient in that all entangled states are used to transmit the secret message and two bits message can be transmitted at one time, the preparation of three-particle entangled state is realized at technique level, and the protocol is feasible to operate. The protocol is al- so verified to be secure for a noise quantum channel.