诱惑态下相位差分量子密钥分发效率分析

Key generation efficiency of practical differential-phase-shift quantum key system with decoy states

讨论基于微弱相干脉冲的相位差分量子密钥分发系统,综合分析系统的安全性问题,给出了密钥生成效率表达式。分析诱惑态对相位差分量子密钥分发系统安全性的影响,并给出了结合诱惑态后的密钥生成效率表达式。分析结果表明,结合诱惑态的相位差分量子密钥分发过程不再受到分光子攻击和序列攻击的威胁,其密钥分发效率与Hoi-Kwong等提出的诱惑态的表述结果一致。实验数据显示,结合诱惑态后的相位差分系统,其安全传输距离得到了进一步提高,量子密钥分发效率提高了约1个数量级。

The security of differential-phase-shift quantum key distribution with weak coherent states is analyzed synthetically. Also, its security combining with decoy states is reevaluated. The expressions of key generation efficiency are given, respectively. The theoretical results indicate that differential-phaseshift quantum key distribution with decoy states is immune from the photon number splitting attacking and the sequential attacking, and its expression of key generation efficiency is identical with that proposed by Hoi-Kwong et al. The experimental data indicate that the combined system not only achieved longer transmission distance, but also improved the key generation efficiency about an order.