自动“即插即用”量子密钥分发

有限资源下即插即用QKD方案的安全性

Security of Plug-and-Play QKD Arrangements with Finite Resources

分析了被动即插即用QKD方案在有限密钥长度情况下的安全性。假设窃听者可以完全访问信道，因此假设是未知且不可信的源。为了考虑BB84协议在量子攻击者的集体攻击下的安全性，全面的处理提供了众所周知的安全密钥速率方程。数值模拟保持最小数量的初始参数恒定的总误差寻求和脉冲数进行。其余参数被优化以产生最大安全密钥速率。提出了两种主要的策略：有和没有两个诱饵状态，包括信号与诱饵关系的优化。

Dual-phase-modulated plug-and-play measurement-device-independent continuous-variable quantum key distribution

We suggest an improved plug-and-play measurement-device-independent (MDI) continuous-variable quantum key distribution (CVQKD) via the dual-phase modulation (DPM), aiming to solve an implementation problem with no extra performance penalty. The synchronous loophole of different lasers from Alice and Bob can be elegantly eliminated in the plug-and-play configuration, which gives birth to the convenient implementation when comparing to the Gaussian-modulated coherent-state protocol. While the local oscillator (LO) can be locally generated by the trusted part Charlie, the LO-aimed attacks can be …

Implementation of a hybrid scheme for coherent plug-and-play quantum key distribution

We experimentally demonstrate a hybrid configuration for Quantum Key Distribution, that combines the simplicity of Distributed Phase Reference protocols with the self-referencing features and polarization insensitivity of the so-called Plug & Play system. Additionally, all the components are arranged in a server-client scheme to allow for practical key distribution. Blank, coherent pulse pair trains are generated at the reception end of the link by means of a pulse sequence and an unbalanced interferometer, and sent to the other end. The emitter writes the qubits by erasing one of the pulses f…

即插即用量子密钥分发系统中利用光子数分辨检测器监测不可信源的被动方案

Passive scheme with a photon-number-resolving detector for monitoring the untrusted source in a plug-and-play quantum-key-distribution system

提出了一种基于分束器和光子数分辨探测器的被动方案，用于在即插即用量子密钥分发系统中应用三强度诱饵态协议验证不可信源的光子统计信息.分析了由于统计涨落和检测噪声引起的实际问题。仿真结果表明，当Alice发送给Bob的光脉冲总数大于10^8，PNR探测器的暗计数率小于0.5计数/脉冲时，该方案可以有效地工作，这在现有技术下是可以实现的。此外，我们提出了一种具有可变光衰减器与阈值检测器相结合的PNR检测器的实际实现。

Plug-and-Play Measurement-Device-Independent Quantum Key Distribution

Quantum key distribution (QKD) gaurantees unconditional communication security based on the laws of quantum physics. However, practical QKD suffers from a number of quantum hackings due to the device imperfections. From the security standpoint, measurement-device-independent quantum key distribution (MDI-QKD) is in the limelight since it eliminates all the possible loopholes in detection. Due to active control units for mode matching between the photons from remote parties, however, the implementation of MDI-QKD is highly impractical. In this article, we propose a novel method in which the ind…

Experimental asymmetric Plug-and-Play Measurement-device-independent quantum key distribution

Measurement-device-independent quantum key distribution (MDI-QKD) is immune to all security loopholes on detection. Previous experiments on MDI-QKD required spatially separated signal lasers and complicated stabilization systems. In this paper, we perform a proof-of-principle experimental demonstration of plug-and-play MDI-QKD over an asymmetric channel setting with a single signal laser, in which the whole system is automatically stabilized in spectrum, polarization, arrival time and phase reference. Both the signal laser and the single-photon detectors are in the possession of a common serve…

A universal, plug-and-play synchronisation scheme for practical quantum networks

We propose and experimentally demonstrate a plug-and-play, practical, and enabling method allowing to synchronize the building blocks of a quantum network in an all-optical way. Our scheme relies on mature and reliable classical telecommunication and non-linear optical technologies and can be implemented in a universal way with off-the-shelf components. Compared to already reported solutions, it allows achieving high-quality synchronization compatible with high network-operation rate and is free from opto-electronic jitters affecting servo-loop based configurations. We test our scheme with a g…

实验即插即用量子硬币翻转

Experimental plug&play quantum coin flipping

执行复杂的密码任务将是未来量子通信网络的基本要素。这些任务基于一些基本的原语，比如抛硬币，两个不信任的团体希望就随机生成的比特达成一致。虽然已知这些原语的量子版本可以提供相对于经典协议的信息理论安全优势，但在实际通信场景中对这种优势的演示仍然难以捉摸。在这里，我们实验性地实现了一个量子抛硬币协议，该协议在适合于城域光网络通信的距离上的性能严格优于经典的。该实现是基于一个实用的即插即用系统，专为量子密钥分发。我们还展示了如何将我们的协议与几乎完全安全的有界对手的掷硬币协议相结合，从而增强了它们的信息理论安全性。我们的研究结果为未来的安全量子通信提供了一个强大的工具箱。

通过插件即插即用架构缓解差分相位移测量-设备无关量子密钥分发中的缺陷

Mitigating imperfections in Differential Phase Shift Measurement-Device-Independent Quantum Key Distribution via Plug-and-Play architecture

本文提出了一种基于差分相位移编码的即插即用方案，以缓解MDI-QKD中因信道不对称性和偏振不匹配导致的安全密钥率问题。

Finite-key-size effect in commercial plug-and-play QKD system

A security evaluation against the finite-key-size effect was performed for a commercial plug-and-play quantum key distribution (QKD) system. We demonstrate the ability of an eavesdropper to force the system to distill key from a smaller length of sifted-key. We also derive a key-rate equation that is specific for this system. This equation provides bounds above the upper bound of secure key under finite-key-size analysis. From this equation and our experimental data, we show that the keys that have been distilled from the smaller sifted-key size fall above our bound. Thus, their security is no…

High efficiency 'plug & play' source of heralded single photons

Reliable generation of single photons is of key importance for fundamental physical experiments and to demonstrate quantum technologies. Waveguide-based photon pair sources have shown great promise in this regard due to their large degree of spectral tunability, high generation rates and long photon coherence times. However, for such a source to have real world applications it needs to be efficiently integrated with fiber-optic networks. We answer this challenge by presenting an alignment-free source of photon pairs in the telecommunications band that maintains heralding efficiency > 50 % even…

Loophole-free plug-and-play quantum key distribution

Robust, simple, and flexible quantum key distribution (QKD) is vital for realising practical applications of this technique. Contrary to typical phase-coded QKD schemes, the plug-and-play QKD design requires only one arm-length-insensitive interferometer without active feedback, in which the noise is automatically compensated by the two-way structure. However, there are certain possible loopholes in the typical plug-and-play designs, which require consideration and strict monitoring. This study proposes a loophole-free plug-and-play QKD scheme with two-way protocol and presents an experimental…

Plug-and-play quantum devices with efficient fiber-quantum dot interface

Incorporating solid-state quantum emitters into optical fiber networks enables the long-distance transmission of quantum information and the remote connection of distributed quantum nodes. However, interfacing quantum emitters with fiber optics encounters several challenges, including low coupling efficiency and stability. Here, we demonstrate a highly efficient fiber-interfacing photonic device that directly launches single photons from quantum dots into a standard FC/PC-connectorized single-mode fiber (SMF28). Optimally designed photonic structures based on hole gratings produce an ultra-nar…

Optical fibre-based (plug-and-play) single photon source using InAsP quantum dot nanowires and gradient-index lens collection

We present a compact, fibre-coupled single photon source using gradient-index (GRIN) lenses and an InAsP semiconductor quantum dot embedded within an InP photonic nanowire waveguide. A GRIN lens assembly is used to collect photons close to the tip of the nanowire, coupling the light immediately into a single mode optical fibre. The system provides a stable, high brightness source of fibre-coupled single photons. Using pulsed excitation, we demonstrate on-demand operation with a single photon purity of 98.5% when exciting at saturation in a device with a source-fibre collection efficiency of 35…