磁光效应对BB84协议的影响分析

Analysis of the effect of magneto-optic effect on BB84 protocol

BB84协议采用四种极化态来进行密钥分发,但在传输的过程中极化态受磁光效应的影响将会发生一定角度的偏转,这将对密钥分发产生非常不利的影响,因此为了顺利得进行量子密钥分发,必须要维持极化态。首先简要介绍了BB84模型以及模型中使用的四种极化态,然后分析了极化态偏转后对量子密钥分发的影响,同时用Matlab进行了仿真,结果表明严重情况下磁光效应将会使通信双方持有的原始密钥不一致。最后给出了一种可行的解决方案。

Four polarization states are used for key distribution in the BB84 protocol, but the polarization states will be rotated for magneto-optic effect during the transmission. Polarization variation will effect distribution of the key, so a means for polarization restoration is required. After the introduction of BB84 protocol and the four states the effect of polarization rotation on quantum key distribution is analyzed. The simulation by Matlab shows the rotation of polarization state will effect key distribution. At last, a feasible method is presented.