scholarly journals Large scale quantum key distribution: challenges and solutions [Invited]

2018 ◽  
Vol 26 (18) ◽  
pp. 24260 ◽  
Author(s):  
Qiang Zhang ◽  
Feihu Xu ◽  
Yu-Ao Chen ◽  
Cheng-Zhi Peng ◽  
Jian-Wei Pan
Keyword(s):  
Quantum Key Distribution ◽  
Large Scale ◽  
Key Distribution

scholarly journals Twin-Field Quantum Key Distribution over 511 km Optical Fiber Linking two Distant Metropolitans

2021 ◽  
Author(s):  
Jiu-Peng Chen ◽  
Chi Zhang ◽  
Yang Liu ◽  
Cong Jiang ◽  
Weijun Zhang ◽  
...  
Keyword(s):  
Quantum State ◽  
Quantum Key Distribution ◽  
Large Scale ◽  
Single Photon ◽  
Key Distribution ◽  
Test System ◽  
Long Distance ◽  
Quantum Networks ◽  
The Cost ◽  
Remarkable Progress

Abstract The basic principle of quantum mechanics guarantee the unconditional security of quantum key distribution (QKD) at the cost of inability of amplification of quantum state. As a result, despite remarkable progress in worldwide metropolitan QKD networks over the past decades, long haul fiber QKD network without trustful relay has not been achieved yet. Here, through sending-or-not-sending (SNS) protocol, we complete a twin field QKD (TF-QKD) and distribute secure keys without any trusted repeater over a 511 km long haul fiber trunk linking two distant metropolitans. Our secure key rate is around 3 orders of magnitudes greater than what is expected if the previous QKD field test system over the same length were applied. The efficient quantum-state transmission and stable single-photon interference over such a long distance deployed fiber paves the way to large-scale fiber quantum networks.

scholarly journals High-speed and Large-scale Privacy Amplification Scheme for Quantum Key Distribution

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Bang-Ying Tang ◽  
Bo Liu ◽  
Yong-Ping Zhai ◽  
Chun-Qing Wu ◽  
Wan-Rong Yu
Keyword(s):  
Compression Ratio ◽  
Quantum Key Distribution ◽  
High Speed ◽  
Large Scale ◽  
Random Number Generation ◽  
Key Distribution ◽  
Key Generation ◽  
Privacy Amplification ◽  
Randomness Extraction ◽  
Computational Resources

Abstract State-of-art quantum key distribution (QKD) systems are performed with several GHz pulse rates, meanwhile privacy amplification (PA) with large scale inputs has to be performed to generate the final secure keys with quantified security. In this paper, we propose a fast Fourier transform (FFT) enhanced high-speed and large-scale (HiLS) PA scheme on commercial CPU platform without increasing dedicated computational devices. The long input weak secure key is divided into many blocks and the random seed for constructing Toeplitz matrix is shuffled to multiple sub-sequences respectively, then PA procedures are parallel implemented for all sub-key blocks with correlated sub-sequences, afterwards, the outcomes are merged as the final secure key. When the input scale is 128 Mb, our proposed HiLS PA scheme reaches 71.16 Mbps, 54.08 Mbps and 39.15 Mbps with the compression ratio equals to 0.125, 0.25 and 0.375 respectively, resulting achievable secure key generation rates close to the asymptotic limit. HiLS PA scheme can be applied to 10 GHz QKD systems with even larger input scales and the evaluated throughput is around 32.49 Mbps with the compression ratio equals to 0.125 and the input scale of 1 Gb, which is ten times larger than the previous works for QKD systems. Furthermore, with the limited computational resources, the achieved throughput of HiLS PA scheme is 0.44 Mbps with the compression ratio equals to 0.125, when the input scale equals up to 128 Gb. In theory, the PA of the randomness extraction in quantum random number generation (QRNG) is same as the PA procedure in QKD, and our work can also be efficiently performed in high-speed QRNG.

scholarly journals Stellar calibration of the single-photon receiver for satellite-to-ground quantum key distribution

2021 ◽  
Vol 2086 (1) ◽  
pp. 012137
Author(s):  
A V Khmelev ◽  
A V Duplinsky ◽  
V L Kurochkin ◽  
Y V Kurochkin
Keyword(s):  
Count Rate ◽  
Quantum Key Distribution ◽  
Large Scale ◽  
Quantum Communication ◽  
Single Photon ◽  
Key Distribution ◽  
Tracking Loop ◽  
Quantum Networks ◽  
Optical Part ◽  
Photon Count

Abstract Satellite quantum communication is the technology that allows to deploy large-scale quantum networks with a communication range of thousands kilometres We report the ground receiver for downlink quantum key distribution (QKD) with satellite. An optical part of this system including an active tracking loop is mounted on a 600-mm Ritchey-Chretien telescope and permits to distinguish polarization states to perform QKD between ground and satellite. Moreover, a procedure of calibration the receiver using stars with known brightness is presented. Measurements of the photon count rate of stars in the spectral range of 845 nm - 855 nm are performed and compared with an estimate.

scholarly journals Explicit asymptotic secret key rate of continuous-variable quantum key distribution with an arbitrary modulation

Quantum ◽  
2021 ◽  
Vol 5 ◽  
pp. 540
Author(s):  
Aurélie Denys ◽  
Peter Brown ◽  
Anthony Leverrier
Keyword(s):  
Quantum Key Distribution ◽  
Coherent States ◽  
Large Scale ◽  
Optimization Problems ◽  
Key Distribution ◽  
Continuous Variable ◽  
Secret Key ◽  
Shift Keying ◽  
Simple Phase ◽  
Numerical Precision

We establish an analytical lower bound on the asymptotic secret key rate of continuous-variable quantum key distribution with an arbitrary modulation of coherent states. Previously, such bounds were only available for protocols with a Gaussian modulation, and numerical bounds existed in the case of simple phase-shift-keying modulations. The latter bounds were obtained as a solution of convex optimization problems and our new analytical bound matches the results of Ghorai et al. (2019), up to numerical precision. The more relevant case of quadrature amplitude modulation (QAM) could not be analyzed with the previous techniques, due to their large number of coherent states. Our bound shows that relatively small constellation sizes, with say 64 states, are essentially sufficient to obtain a performance close to a true Gaussian modulation and are therefore an attractive solution for large-scale deployment of continuous-variable quantum key distribution. We also derive similar bounds when the modulation consists of arbitrary states, not necessarily pure.

scholarly journals The Performance of Satellite-Based Links for Measurement-Device-Independent Quantum Key Distribution

Entropy ◽  
2021 ◽  
Vol 23 (8) ◽  
pp. 1010
Author(s):  
Guoqi Huang ◽  
Qin Dong ◽  
Wei Cui ◽  
Rongzhen Jiao
Keyword(s):  
Communication Network ◽  
Optical Fiber ◽  
Quantum Key Distribution ◽  
Large Scale ◽  
Quantum Communication ◽  
Weather Conditions ◽  
Key Distribution ◽  
Long Distance ◽  
Measurement Device ◽  
Measurement Device Independent

Measurement-device-independent quantum key distribution (MDI-QKD) protocol has high practical value. Satellite-based links are useful to build long-distance quantum communication network. The model of satellite-based links for MDI-QKD was proposed but it lacks practicality. This work further analyzes the performance of it. First, MDI-QKD and satellite-based links model are introduced. Then considering the operation of the satellite the performance of their combination is studied under different weather conditions. The results may provide important references for combination of optical-fiber-based links on the ground and satellite-based links in space, which is helpful for large-scale quantum communication network.

scholarly journals Field trial of a three-state quantum key distribution scheme in the Florence metropolitan area

2019 ◽  
Vol 6 (1) ◽  
Author(s):  
Davide Bacco ◽  
Ilaria Vagniluca ◽  
Beatrice Da Lio ◽  
Nicola Biagi ◽  
Adriano Della Frera ◽  
...  
Keyword(s):  
Metropolitan Area ◽  
Quantum Key Distribution ◽  
Large Scale ◽  
Key Distribution ◽  
Telecommunication Networks ◽  
Current Field ◽  
Classical Communication ◽  
Distribution Scheme ◽  
Synchronization Signal ◽  
Fiber Link

Abstract In-field demonstrations in real-world scenarios boost the development of a rising technology towards its integration in existing infrastructures. Although quantum key distribution (QKD) devices are already adopted outside the laboratories, current field implementations still suffer from high costs and low performances, preventing this emerging technology from a large-scale deployment in telecommunication networks. Here we present a simple, practical and efficient QKD scheme with finite-key analysis, performed over a 21 dB-losses fiber link installed in the metropolitan area of Florence (Italy). Coexistence of quantum and weak classical communication is also demonstrated by transmitting an optical synchronization signal through the same fiber link.

scholarly journals Coherent-State-Based Twin-Field Quantum Key Distribution

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Hua-Lei Yin ◽  
Zeng-Bing Chen
Keyword(s):  
Coherent State ◽  
Communication Networks ◽  
Quantum Key Distribution ◽  
Large Scale ◽  
Key Distribution ◽  
Entanglement Swapping ◽  
Secret Key ◽  
Entanglement Purification ◽  
Classical Communication ◽  
Security Proof

Abstract Large-scale quantum communication networks are still a huge challenge due to the rate-distance limit of quantum key distribution (QKD). Recently, twin-field (TF) QKD has been proposed to overcome this limit. Here, we prove that coherent-state-based TF-QKD is a time-reversed entanglement protocol, where the entanglement generation is realized with entanglement swapping operation via an entangled coherent state measurement. We propose a coherent-state-based TF-QKD with optimal secret key rate under symmetric and asymmetric channels by using coherent state and cat state coding. Furthermore, we show that our protocol can be converted to all recent coherent-state-based TF-QKD protocols by using our security proof. By using the entanglement purification with two-way classical communication, we improve the transmission distance of all coherent-state-based TF-QKD protocols.

scholarly journals Performance Analysis of Quantum Key Distribution Technology for Power Business

2020 ◽  
Vol 10 (8) ◽  
pp. 2906
Author(s):  
Bingzhen Zhao ◽  
Xiaoming Zha ◽  
Zhiyu Chen ◽  
Rui Shi ◽  
Dong Wang ◽  
...  
Keyword(s):  
Performance Indicators ◽  
Quantum Key Distribution ◽  
Large Scale ◽  
Key Distribution ◽  
System Stability ◽  
Data Traffic ◽  
Transmission Losses ◽  
Grid Environments ◽  
Actual Environment ◽  
Environment Performance

Considering the complexity of power grid environments and the diversity of power communication transmission losses, this study proposes a quantum key distribution (QKD) network structure suitable for power business scenarios. Through simulating the power communication transmission environment, performance indicators of quantum channels and data interaction channels in power QKD systems are tested and evaluated from six aspects, such as distance loss, galloping loss, splice loss, data traffic, encryption algorithm and system stability. In the actual environment, this study combines the production business to build a QKD network suitable for power scenarios, and conducts performance analyses. The experimental results show that power QKD technologies can meet the operation index requirements of power businesses, as well as provide a reference for large-scale applications of the technology.

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