National Laboratory of Solid State Microstructures and School of Physics, Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing 210093, China.
Beijing National Laboratory for Condensed Matter Physics and Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China; MatricTime Digital Technology Co. Ltd., Nanjing 211899, China.
Sci Bull (Beijing). 2022 Nov 15;67(21):2167-2175. doi: 10.1016/j.scib.2022.10.010. Epub 2022 Oct 14.
The security of quantum key distribution (QKD) is severely threatened by discrepancies between realistic devices and theoretical assumptions. Recently, a significant framework called the reference technique was proposed to provide security against arbitrary source flaws under current technology such as state preparation flaws, side channels caused by mode dependencies, the Trojan horse attacks and pulse correlations. Here, we adopt the reference technique to prove security of an efficient four-phase measurement-device-independent QKD using laser pulses against potential source imperfections. We present a characterization of source flaws and connect them to experiments, together with a finite-key analysis against coherent attacks. In addition, we demonstrate the feasibility of our protocol through a proof-of-principle experimental implementation and achieve a secure key rate of 253 bps with a 20 dB channel loss. Compared with previous QKD protocols with imperfect devices, our study considerably improves both the secure key rate and the transmission distance, and shows application potential in the practical deployment of secure QKD with device imperfections.
量子密钥分发（QKD）的安全性受到现实设备与理论假设之间差异的严重威胁。最近，提出了一种名为参考技术的重要框架，可以在当前技术下（如状态制备缺陷、由模式依赖性引起的侧信道、木马攻击和脉冲相关性）针对任意源缺陷提供安全性。在这里，我们采用参考技术来证明使用激光脉冲的高效四相位测量设备无关 QKD 对潜在源不完美的安全性。我们对源缺陷进行了特征描述，并将其与实验联系起来，同时针对相干攻击进行了有限密钥分析。此外，我们通过原理验证实验实现证明了我们协议的可行性，并在 20dB 信道损耗下实现了 253 bps 的安全密钥率。与以前使用不完美设备的 QKD 协议相比，我们的研究大大提高了安全密钥率和传输距离，并展示了在具有设备缺陷的实际安全 QKD 部署中的应用潜力。
