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 atttacks 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.

翻译：量子钥匙分布的安全受到现实装置和理论假设之间差异的严重威胁。最近,提出了一个称为参考技术的重要框架,以在目前技术下防止任意的来源缺陷,如国家准备缺陷、模式依赖造成的侧道、特洛伊马背背面和脉冲相关关系。这里,我们采用参考技术,用激光脉冲防止潜在来源缺陷,证明有效的四阶段测量-独立QKD的安全性。我们提出了源缺陷的特征,并将它们与实验联系起来,同时对连贯攻击进行限定钥匙分析。此外,我们还通过原则证据实验实施,展示了我们的协议的可行性,并实现了253 bps的安全关键率,损失了20 dB通道。与先前的有不完善装置的QKD协议相比,我们的研究大大改进了安全钥匙率和传输距离,并展示了安全QKD与装置不完善的实际应用潜力。