论文标题
使用Flag-State Supashing模型提高不平衡相编码BB84协议的关键速率
Improving key rates of the unbalanced phase-encoded BB84 protocol using the flag-state squashing model
论文作者
论文摘要
所有相编码的BB84实现都具有信号状态，实践中具有不平衡的幅度。因此，先验的原始安全性分析不适用于它们。先前的安全性证明使用多光子脉冲的信号标记来恢复常规BB84的行为。这是过于保守的，对于信号不平衡，光子数分裂攻击不会向EVE泄漏全部信息。在这项工作中，我们利用旗帜状态挤压模型在我们的分析中保留多光子生成的私人信息的某些部分。使用数值证明技术，与先前发表的低损失制度结果相比，我们获得的关键率明显更高。事实证明，在某些参数制度中，不受信任的黑暗计数的通常场景遇到了概念上的困难。因此，我们在本文中也讨论了可信赖的黑暗计数情景。当已知一部分被信任的设备引起总损失的一部分时，我们还报告了关键利率的收益。我们强调，如果不修改实验设置，就可以实现所有这些关键率提高。
All phase-encoded BB84 implementations have signal states with unbalanced amplitudes in practice. Thus, the original security analyses a priori do not apply to them. Previous security proofs use signal tagging of multi-photon pulses to recover the behaviour of regular BB84. This is overly conservative, as for unbalanced signals, the photon-number splitting attack does not leak full information to Eve. In this work, we exploit the flag-state squashing model to preserve some parts of the multi-photon generated private information in our analysis. Using a numerical proof technique, we obtain significantly higher key rates compared with previously published results in the low-loss regime. It turns out that the usual scenario of untrusted dark counts runs into conceptual difficulties in some parameter regime. Thus, we discuss the trusted dark count scenario in this paper as well. We also report a gain in key rates when part of the total loss is known to be induced by a trusted device. We highlight that all these key rate improvements can be achieved without modification of the experimental setup.
