基于BB84协议的实际QKD系统的窃听问题研究

Eavesdropping of Practical QKD System Based on BB84 Protocol

基于实际量子密钥分配系统中所使用的强衰减的激光脉冲并不是单光子,量子密钥分配的信道不是无损耗的,窃听者的技术能力也不是无限的这些具体问题。

Practical implementations of quantum key distribution systems use attenuated laser pulses as the signal source rather than single photons. The channels used to transmit are lossy. On the basis of above two points, a combining eavesdropping strategy of intercept resend and beamsplitting is discussed in terms of eavesdropper′s technology requirement. At last, a maximum disturbance bound is derived for a given mean photon number and transmission length. Eavesdropper can be detected with the bound.