Challenges
Datasets
Workspaces
Papers
Discussions
Leaderboard
Log inSign up
Challenges
Datasets
Workspaces
Papers
Discussions
Leaderboard
Blog
Job Board
Q3AS

© 2026 Aqora Quantum S.A.S.

TermsPrivacyLegal Notice

Communications in Theoretical Physics

Asymmetric twin-field quantum key distribution with both statistical and intensity fluctuations

Shao-Fu He, Yang Wang, Jia-Ji Li, Wan‐Su Bao

Published May 18, 2020• 6 citations
Publisher

Abstract

Abstract Twin-field quantum key distribution (TF-QKD) is a disruptive innovation which is able to overcome the rate-distance limit of QKD without trusted relays. Since the proposal of the first TF-QKD protocol, theoretical and experimental breakthroughs have been made to enhance its ability. However, there still exist some practical issues waiting for settlement. In this paper, we examine the performances of asymmetric TF-QKD protocol with unstable light sources and limited data sizes. The statistical fluctuations of the parameters are estimated employing Azuma’s inequality. Through numerical simulations, we compare the secret key rates of the asymmetric TF-QKD protocol with different data sizes and variant intensity fluctuation magnitudes. Our results demonstrate that both statistical and intensity fluctuations have significant impacts on the performance of asymmetric TF-QKD.

DOI
10.1088/1572-9494/ab8a11

Related papers

Finite-key analysis for a practical decoy-state twin-field quantum key distribution

Shao-Fu He, Yang Wang, Hongwei Li +1 more

Twin-field quantum key distribution (TF-QKD), which is immune to all possible detector side channel attacks, enables two remote legitimate users to perform secure communications without quantum repeaters. With the help of a central node, TF-QKD is expected to overcome the linear key-rate constraint using current technologies. However, the security of the former TF-QKD protocols relies on the hypothesis of infinite-key and stable sources. In this paper, we present the finite-key analysis of a practical decoy-state twin-field quantum key distribution with variant statistical fluctuation models. We examine the composable security of the protocol with intensity fluctuations of unstable sources employing Azuma's inequality. Our simulation results indicate that the secret key rate is able to surpass the linear key-rate bound with limited signal pulses and intensity fluctuations. In addition, the effect of intensity fluctuations is extremely significant for small size of total signals.

arXiv:1910.12416•Oct 28, 2019•0 citations

Finite-key analysis of asymmetric phase-matching quantum key distribution with unstable sources

Xiaoxu Zhang, Yang Wang, Mu-Sheng Jiang +3 more

The twin-field quantum key distribution (TF-QKD) protocol has been studied widely to overcome the linear bound, and several variations of the TF-QKD protocol have been proposed to improve security and practicality. One variation called the phase-matching QKD (PM-QKD) protocol develops an optical-mode-based security; simultaneously, it has a quadratic improvement of key rate without either basis choice or phase locking. So far, the main research work of the PM-QKD protocol has focused on symmetric channels. However, it is quite common that the two channels have asymmetric transmittances in real life. In this paper, we discuss the effects of asymmetric channels on the PM-QKD protocol; to reach a much better performance and achieve a higher key rate, the intensity must be optimized to compensate for channel asymmetry. We also study the practical issues of finite-key effects and intensity fluctuations, which have significant effects on the key rate of PM-QKD.

Journal of the Optical Society of America B•Jan 11, 2021•6 citations

Practical issues of twin-field quantum key distribution

Feng-Yu Lu, Zhen−Qiang Yin, Rong Wang +8 more

Abstract Twin-field quantum key distribution(TF-QKD) protocol and its variants, such as phase-matching QKD, sending-or-not-sending QKD and no phase post-selection TF-QKD(NPP-TFQKD), are very promising for long-distance applications. However, there are still some gaps between theory and practice in these protocols. Concretely, a finite-key size analysis is still missing, and the intensity fluctuations are not taken into account. To address the finite-key size effect, we first give the key rate of NPP-TFQKD against collective attack in finite-key size region and then prove it can be against coherent attack. To deal with the intensity fluctuations, we present an analytical formula of 4-intensity decoy state NPP-TFQKD and a practical intensity fluctuation model. Finally, through detailed simulations, we show NPP-TFQKD can still keep its superiority of high key rate and long achievable distance.

arXiv:1901.04264•New Journal of Physics•Nov 22, 2019•36 citations

Asymmetric twin-field quantum key distribution

Federico Grasselli, Álvaro Navarrete, Marcos Curty

Abstract Twin-Field (TF) quantum key distribution (QKD) is a major candidate to be the new benchmark for far-distance QKD implementations, since its secret key rate can overcome the repeaterless bound by means of a simple interferometric measurement. Many variants of the original protocol have been recently proven to be secure. Here, we focus on the TF-QKD type protocol proposed by Curty et al (2019 NPJ Quantum Inf. 5 64), which can provide a high secret key rate and whose practical feasibility has been demonstrated in various recent experiments. The security of this protocol relies on the estimation of certain detection probabilities (yields) through the decoy-state technique. Analytical bounds on the relevant yields have been recently derived assuming that both parties use the same set of decoy intensities, thus providing sub-optimal key rates in asymmetric-loss scenarios. Here we derive new analytical bounds when the parties use either two, three or four independent decoy intensity settings each. With the new bounds we optimize the protocol’s performance in asymmetric-loss scenarios and show that the protocol is robust against uncorrelated intensity fluctuations affecting the parties’ lasers.

arXiv:1907.05256•New Journal of Physics•Oct 28, 2019•36 citations

Finite-key-size Effect in Asymmetric Twin-Field Quantum Key Distribution

Joo Youn Park, Jun Heo

Twin-Field(TF) quantum key distribution(QKD) is attracting attention due to the possibility of implementing long-range QKD. However, due to the finite-size effect, the secret key rate becomes relatively low. The statistical fluctuation analysis of the four-intensity decoy-state asymmetric TF-QKD system is considered in this study, and optimized parameters for the Gaussian approximation method are also presented.

International Conference on Information and Communication Technology Convergence (ICTC)•Oct 20, 2021•1 citation

Sending-or-not-sending twin-field quantum key distribution in practice

Zong‐Wen Yu, Xiao-Long Hu, Cong Jiang +2 more

Recently, the twin field quantum key distribution (TF-QKD) protocols have been investigated extensively. In particular, an efficient protocol for TF-QKD with sending or not sending the coherent state has been given in. Here in this paper, we present results of practical sending-or-not-sending (SNS) twin field quantum key distribution. In real-life implementations, we need consider the following three requirements, a few different intensities rather than infinite number of different intensities, a phase slice of appropriate size rather than infinitely small size and the statistical fluctuations. We first show the decoy-state method with only a few different intensities and a phase slice of appropriate size. We then give a statistical fluctuation analysis for the decoy-state method. Numerical simulation shows that, the performance of our method is comparable to the asymptotic case for which the key size is large enough. Our method can beat the PLOB bound on secret key capacity. Our results show that practical implementations of the SNS quantum key distribution can be both secure and efficient.

arXiv:1807.09891•Scientific Reports•Feb 28, 2019•89 citations
Abstract Twin-field quantum key distribution (TF-QKD) is a disruptive innovation which is able to overcome the rate-distance limit of QKD without trusted relays. Since the proposal of the first TF-QKD protocol, theoretical and experimental breakthroughs have been made to enhance its ability. However, there still exist some practical issues waiting for settlement. In this paper, we examine the performances of asymmetric TF-QKD protocol with unstable light sources and limited data sizes. The statistical fluctuations of the parameters are estimated employing Azuma’s inequality. Through numerical simulations, we compare the secret key rates of the asymmetric TF-QKD protocol with different data sizes and variant intensity fluctuation magnitudes. Our results demonstrate that both statistical and intensity fluctuations have significant impacts on the performance of asymmetric TF-QKD.
Twin-field quantum key distribution (TF-QKD), which is immune to all possible detector side channel attacks, enables two remote legitimate users to perform secure communications without quantum repeaters. With the help of a central node, TF-QKD is expected to overcome the linear key-rate constraint using current technologies. However, the security of the former TF-QKD protocols relies on the hypothesis of infinite-key and stable sources. In this paper, we present the finite-key analysis of a practical decoy-state twin-field quantum key distribution with variant statistical fluctuation models. We examine the composable security of the protocol with intensity fluctuations of unstable sources employing Azuma's inequality. Our simulation results indicate that the secret key rate is able to surpass the linear key-rate bound with limited signal pulses and intensity fluctuations. In addition, the effect of intensity fluctuations is extremely significant for small size of total signals.
The twin-field quantum key distribution (TF-QKD) protocol has been studied widely to overcome the linear bound, and several variations of the TF-QKD protocol have been proposed to improve security and practicality. One variation called the phase-matching QKD (PM-QKD) protocol develops an optical-mode-based security; simultaneously, it has a quadratic improvement of key rate without either basis choice or phase locking. So far, the main research work of the PM-QKD protocol has focused on symmetric channels. However, it is quite common that the two channels have asymmetric transmittances in real life. In this paper, we discuss the effects of asymmetric channels on the PM-QKD protocol; to reach a much better performance and achieve a higher key rate, the intensity must be optimized to compensate for channel asymmetry. We also study the practical issues of finite-key effects and intensity fluctuations, which have significant effects on the key rate of PM-QKD.
Abstract Twin-field quantum key distribution(TF-QKD) protocol and its variants, such as phase-matching QKD, sending-or-not-sending QKD and no phase post-selection TF-QKD(NPP-TFQKD), are very promising for long-distance applications. However, there are still some gaps between theory and practice in these protocols. Concretely, a finite-key size analysis is still missing, and the intensity fluctuations are not taken into account. To address the finite-key size effect, we first give the key rate of NPP-TFQKD against collective attack in finite-key size region and then prove it can be against coherent attack. To deal with the intensity fluctuations, we present an analytical formula of 4-intensity decoy state NPP-TFQKD and a practical intensity fluctuation model. Finally, through detailed simulations, we show NPP-TFQKD can still keep its superiority of high key rate and long achievable distance.
Abstract Twin-Field (TF) quantum key distribution (QKD) is a major candidate to be the new benchmark for far-distance QKD implementations, since its secret key rate can overcome the repeaterless bound by means of a simple interferometric measurement. Many variants of the original protocol have been recently proven to be secure. Here, we focus on the TF-QKD type protocol proposed by Curty et al (2019 NPJ Quantum Inf. 5 64), which can provide a high secret key rate and whose practical feasibility has been demonstrated in various recent experiments. The security of this protocol relies on the estimation of certain detection probabilities (yields) through the decoy-state technique. Analytical bounds on the relevant yields have been recently derived assuming that both parties use the same set of decoy intensities, thus providing sub-optimal key rates in asymmetric-loss scenarios. Here we derive new analytical bounds when the parties use either two, three or four independent decoy intensity settings each. With the new bounds we optimize the protocol’s performance in asymmetric-loss scenarios and show that the protocol is robust against uncorrelated intensity fluctuations affecting the parties’ lasers.
Recently, the twin field quantum key distribution (TF-QKD) protocols have been investigated extensively. In particular, an efficient protocol for TF-QKD with sending or not sending the coherent state has been given in. Here in this paper, we present results of practical sending-or-not-sending (SNS) twin field quantum key distribution. In real-life implementations, we need consider the following three requirements, a few different intensities rather than infinite number of different intensities, a phase slice of appropriate size rather than infinitely small size and the statistical fluctuations. We first show the decoy-state method with only a few different intensities and a phase slice of appropriate size. We then give a statistical fluctuation analysis for the decoy-state method. Numerical simulation shows that, the performance of our method is comparable to the asymptotic case for which the key size is large enough. Our method can beat the PLOB bound on secret key capacity. Our results show that practical implementations of the SNS quantum key distribution can be both secure and efficient.