Practical Security Problem of Six States QKD Protocol
实际量子密钥分配扩展BB84协议窃听下的安全性分析

It is used attenuated laser pulses as the signal source rather than single photons in practical QKD system. The channels is used to transmit are lossy. Eve's eavesdropping ability is limited. On the basis of above three points,a eavesdropping device is presented. Meanwhile,the study is analyzed the calculation of the effective average Alice/Eve mutual information and Alice/Bob error rate's upper limit in six states QKD protocol. It shows that Breidbart eavesdropping/beamsplitter is the more effective one compared with Breidbart eavesdropping(B/B strategy).