多用户量子密钥分配方案及协议设计

Multi-user quantum key distribution model and the correlative protocol

在纠缠态和纠缠交换的基础上,提出一种多用户量子密钥分发方案及协议.该方案只需n个量子信道就可实现n用户系统两两之间的密钥分发.量子交换中心通过纠缠交换建立量子信道,量子信道一旦建立,系统中任意两个用户即可进行量子密钥分发.还探讨了系统容量问题,结合话务量的概念,给出了量子Bell基测量单元数m与用户数n的关系式.量子交换中心完成纠缠交换后不再介入密钥分发,从而保证了通信的安全性。

We propose a Multi-user Quantum Key Distribution （MQKD） protocol, which only needs n quantum channels for a communication system of n users to realize the protocol with entangled states and entanglement swapping. By the quantum mediator, any two among n users of the system can communicate with each other, even though there is no direct quantum channel between them. Based on the traffic theory, we present a relationship formula of the number of user n and the number of Bell state measurement units rn. Because entanglement swapping entangles the quantum states of the two users, the quantum mediator has no way to fraudulently intervene in or eavesdrop on the communication.