scholarly journals Finite-key analysis for twin-field quantum key distribution with composable security

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Hua-Lei Yin ◽  
Zeng-Bing Chen
Keyword(s):  
Coherent State ◽  
Quantum Key Distribution ◽  
Key Distribution ◽  
Practical Implementation ◽  
Fluctuation Analysis ◽  
Statistical Fluctuation ◽  
Secret Key ◽  
Quantum Repeater ◽  
Long Distance ◽  
Security Proof

AbstractLong-distance quantum key distribution (QKD) has long time seriously relied on trusted relay or quantum repeater, which either has security threat or is far from practical implementation. Recently, a solution called twin-field (TF) QKD and its variants have been proposed to overcome this challenge. However, most security proofs are complicated, a majority of which could only ensure security against collective attacks. Until now, the full and simple security proof can only be provided with asymptotic resource assumption. Here, we provide a composable finite-key analysis for coherent-state-based TF-QKD with rigorous security proof against general attacks. Furthermore, we develop the optimal statistical fluctuation analysis method to significantly improve secret key rate in high-loss regime. The results show that coherent-state-based TF-QKD is practical and feasible, with the potential to apply over nearly one thousand kilometers.

scholarly journals Discrete Modulation Source Enhancement for Continuous Variable Quantum Key Distribution through Photon Catalyzing

2020 ◽  
Author(s):  
Zhengchun Zhou ◽  
Shanhua Zou ◽  
Yun Mao ◽  
Tongcheng Huang ◽  
Ying Guo
Keyword(s):  
Quantum Key Distribution ◽  
Key Distribution ◽  
Continuous Variable ◽  
High Rate ◽  
Practical Implementation ◽  
Statistical Fluctuation ◽  
Secret Key ◽  
Long Distance ◽  
Transmission Distance ◽  
Source Preparation

Establishing global high-rate secure communications is a potential application of continuous-variable quantum key distribution (CVQKD) but also challenging for long-distance transmissions in metropolitan areas. The discrete modulation(DM) can make up for the shortage of transmission distance that has a unique advantage against all side-channel attacks, however its further performance improvement requires source preparation in the presence of noise and loss. Here, we consider the effects of photon catalysis (PC) on the DM-involved source preparation for lengthening the maximal transmission distance of the CVQKD system. We address a zero-photon catalysis (ZPC)-based source preparation for enhancing the DM-CVQKD system. The statistical fluctuation due to the finite length of data is taken into account for the practical security analysis. Numerical simulations show that the ZPC-based DM-CVQKD system can not only achieve the extended maximal transmission distance, but also contributes to the reasonable increase of the secret key rate. This approach enables the DM-CVQKD to tolerate lower reconciliation efficiency, which may promote the practical implementation solutions compatible with classical optical communications using state-of-the-art technology.

Statistical Fluctuation Analysis of Quantum Key Distribution Protocols Based on Heralded Pair Coherent State

2020 ◽  
Vol 40 (7) ◽  
pp. 0727002
Author(s):  
何业锋 He Yefeng ◽  
赵艳坤 Zhao Yankun ◽  
郭佳瑞 Guo Jiarui ◽  
李春雨 Li Chunyu
Keyword(s):  
Coherent State ◽  
Quantum Key Distribution ◽  
Key Distribution ◽  
Fluctuation Analysis ◽  
Statistical Fluctuation ◽  
Pair Coherent State

scholarly journals Lengthening Transmission Distance of Continuous Variable Quantum Key Distribution with Discrete Modulation through Photon Catalyzing

2020 ◽  
Vol 10 (21) ◽  
pp. 7770
Author(s):  
Zhengchun Zhou ◽  
Shanhua Zou ◽  
Tongcheng Huang ◽  
Ying Guo
Keyword(s):  
Quantum Key Distribution ◽  
Key Distribution ◽  
Continuous Variable ◽  
Statistical Fluctuation ◽  
Secret Key ◽  
Long Distance ◽  
Long Distance Transmission ◽  
Transmission Distance ◽  
Secure Networks ◽  
Source Preparation

Establishing global secure networks is a potential implementation of continuous-variable quantum key distribution (CVQKD) but it is also challenged with respect to long-distance transmission. The discrete modulation (DM) can make up for the shortage of transmission distance in that it has a unique advantage against all side-channel attacks; however, its further performance improvement requires source preparation in the presence of noise and loss. Here, we consider the effects of photon catalysis (PC) on the DM-involved source preparation for improving the transmission distance. We address a zero-photon-catalysis (ZPC)-based source preparation for enhancing the DM–CVQKD system. The statistical fluctuation is taken into account for the practical security analysis. Numerical simulations show that the ZPC-based source preparation can not only achieve the long-distance transmission, but also contributes to the reasonable increase of the secret key rate.

scholarly journals Practical Analysis of Sending or Not-Sending Twin-Field Quantum Key Distribution with Frequency Side Channels

2021 ◽  
Vol 11 (20) ◽  
pp. 9560
Author(s):  
Yi-Fei Lu ◽  
Mu-Sheng Jiang ◽  
Yang Wang ◽  
Xiao-Xu Zhang ◽  
Fan Liu ◽  
...  
Keyword(s):  
Quantum Key Distribution ◽  
Key Distribution ◽  
Practical Implementation ◽  
Side Channel ◽  
Secret Key ◽  
Side Channel Attack ◽  
Long Distance ◽  
Side Channels ◽  
The Subject ◽  
Distance Limit

The twin-field quantum key distribution (TF-QKD) and its variants can overcome the fundamental rate-distance limit of QKD. However, their physical implementations with the side channels remain the subject of further research. We test the side channel of a type of external intensity modulation that applies a Mach–Zehnder-type electro-optical intensity modulator, which shows the distinguishability of the signal and decoy states in the frequency domain. Based on this security loophole, we propose a side-channel attack, named the passive frequency-shift attack, on the imperfect implementation of the sending or not-sending (SNS) TF-QKD protocol. We analyze the performance of the SNS protocol with the actively odd-parity pairing (AOPP) method under the side-channel attack by giving the formula of the upper bound of the real secret key rate and comparing it with the lower bound of the secret key rate under Alice and Bob’s estimation. The simulation results quantitatively show the effectiveness of the attack on the imperfect devices at a long distance. Our results emphasize the importance of practical security at the light source and might provide a valuable reference for device selection in the practical implementation of the SNS protocol.

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 A largely self-contained and complete security proof for quantum key distribution

Quantum ◽  
2017 ◽  
Vol 1 ◽  
pp. 14 ◽  
Author(s):  
Marco Tomamichel ◽  
Anthony Leverrier
Keyword(s):  
Quantum Key Distribution ◽  
Estimation Error ◽  
Security Analysis ◽  
Key Distribution ◽  
Operational Definition ◽  
Uncertainty Relations ◽  
Secret Key ◽  
Security Proof ◽  
Key Length ◽  
Definition Of

In this work we present a security analysis for quantum key distribution, establishing a rigorous tradeoff between various protocol and security parameters for a class of entanglement-based and prepare-and-measure protocols. The goal of this paper is twofold: 1) to review and clarify the stateof-the-art security analysis based on entropic uncertainty relations, and 2) to provide an accessible resource for researchers interested in a security analysis of quantum cryptographic protocols that takes into account finite resource effects. For this purpose we collect and clarify several arguments spread in the literature on the subject with the goal of making this treatment largely self-contained. More precisely, we focus on a class of prepare-and-measure protocols based on the Bennett-Brassard (BB84) protocol as well as a class of entanglement-based protocols similar to the Bennett-Brassard-Mermin (BBM92) protocol. We carefully formalize the different steps in these protocols, including randomization, measurement, parameter estimation, error correction and privacy amplification, allowing us to be mathematically precise throughout the security analysis. We start from an operational definition of what it means for a quantum key distribution protocol to be secure and derive simple conditions that serve as sufficient condition for secrecy and correctness. We then derive and eventually discuss tradeoff relations between the block length of the classical computation, the noise tolerance, the secret key length and the security parameters for our protocols. Our results significantly improve upon previously reported tradeoffs.

SECURITY OF QUANTUM KEY DISTRIBUTION WITH STRONG PHASE-REFERENCE PULSE

2005 ◽  
Vol 03 (supp01) ◽  
pp. 75-86
Author(s):  
MASATO KOASHI
Keyword(s):  
Coherent State ◽  
Quantum Key Distribution ◽  
Single Photon ◽  
Key Distribution ◽  
Secret Key ◽  
Single Photon Source ◽  
Reference Pulse ◽  
High Loss ◽  
The One ◽  
Photon Source

In the BB84 protocol with a perfect single photon source, the key rate decreases linearly with the transmission η of the channel. If we simply replace this source with a weak coherent-state pulse, the key rate drops more rapidly (as O(η2)) since the presence of multiple photons favors the eavesdropper. Here we discuss the unconditional security of a quantum key distribution protocol in which bit values are encoded in the phase of a weak coherent-state pulse relative to a strong reference pulse, which is essentially the one proposed by Bennett in 1992 (the B92 scheme). We show that in the limit of high loss in the transmission channel, we can construct a secret key with a rate proportional to the transmission η of the channel.

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