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

arXiv:2407.20302 · Physical Review Applied

Trusted-source-noise model of discrete-modulated continuous-variable quantum key distribution

Mingze Wu, Junhui Li, Bingjie Xu, Song Yu, Yichen Zhang

Published Sep 11, 2024• 7 citations
arXivHTMLPDF

Abstract

The system's source noise affects the practical performance of discrete-modulated continuous-variable quantum key distribution. The good news: This noise exists inside the system and cannot be exploited by eavesdroppers, so it can be trusted. However, a lack of appropriate modeling leaves a security-key-rate gap, omitting this trusted noise. The authors propose a model for trusted source noise in the discrete-modulated protocol, successfully mitigating the negative impact of an imperfect source on system performance while maintaining security of the protocol, and thus promoting practical deployment.

DOI
10.1103/physrevapplied.22.034024

Related papers

Analysis of imperfections in practical continuous-variable quantum key distribution

Paul Jouguet, Sébastien Kunz-Jacques, Eleni Diamanti +1 more

As quantum key distribution becomes a mature technology, it appears clearly that some assumptions made in the security proofs cannot be justified in practical implementations. This might open the door to possible side-channel attacks. We examine several discrepancies between theoretical models and experimental setups in the case of continuous-variable quantum key distribution. We study in particular the impact of an imperfect modulation on the security of Gaussian protocols and show that approximating the theoretical Gaussian modulation with a discrete one is sufficient in practice. We also address the issue of properly calibrating the detection setup and in particular the value of the shot noise. Finally, we consider the influence of phase noise in the preparation stage of the protocol and argue that taking this noise into account can improve the secret key rate because this source of noise is not controlled by the eavesdropper.

arXiv:1206.6357•Physical Review A•Sep 10, 2012•233 citations

Trusted Detector Noise Analysis for Discrete Modulation Schemes of Continuous-Variable Quantum Key Distribution

Jie Lin, Norbert Lütkenhaus

Discrete-modulated continuous-variable quantum key distribution protocols are promising candidates for large-scale deployment due to the large technological overlap with deployed modern optical communication devices. The security of discrete modulation schemes has previously been analyzed in the ideal detector scenario in the asymptotic limit. In this work, we calculate asymptotic key rates against collective attacks in the trusted detector noise scenario. Our results show that we can thus cut out most of the effect of detector noise and obtain asymptotic key rates similar to those had we access to ideal detectors.

arXiv:2006.06166•Physical Review Applied•Dec 9, 2020•50 citations

Amplitude-boosting attack against practical discrete-modulated continuous-variable quantum key distribution

Mingze Wu, Yiming Bian, Junhui Li +2 more

Discrete-modulated continuous-variable quantum key distribution offers significant practical deployment advantages due to its straightforward state preparation and high compatibility with coherent optical communication systems. However, security analysis and parameter estimation of discrete-modulated protocol are different with Gaussian-modulated protocols, which could cause different practical security problems. Herein, we investigate the amplitude-boosting attack against discrete-modulated continuous-variable quantum key distribution systems and assess its impact on system performance. Our findings reveal that this attack could cause overestimation of secret key rate perceived by Alice and Bob, thereby opening a security loophole, and the vulnerability could be severer than Gaussian modulation. Additionally, we summarize defensive countermeasures, marking a crucial step towards enhancing the practical security of discrete-modulated continuous-variable quantum key distribution.

Optics Express•Aug 26, 2024•5 citations

Security boundaries of two-way continuous-variable quantum key distribution under multiple source imperfections

Ningyi Mao, Hang Zhang, Zhiyue Zuo +3 more

Abstract Two-way continuous-variable quantum key distribution protocol, where the parties make a double use of the quantum channel, shows the general superadditivity in the security thresholds, which are proven to be higher than that of the classical one-way protocol. However, all existing security proofs for two-way protocols assume perfect source devices or a trusted source noise, which is hard to ensure in a practical system. In this paper, the effects of multiple source fluctuations on the security of the two-way protocol are proposed, where Eve may have access to the intensity fluctuation information with an arbitrary random distribution. This work is comprehensive of several practical scenarios, encompassing both ON and OFF configurations, with and without the assumption that trusted users can access the fluctuation information. The analysis shows that when the users have no fluctuation information, the intensity fluctuation effect in the ON configuration should be modeled as an additional thermal noise rather than being described by a beam splitter model as in the general one-way protocol. In addition, this untrusted noise is only related to the intensity fluctuation variance but has no relation to its distribution. Finally, the tagging idea is applied to the two-way protocol to obtain a conservative secure key.

Journal of Physics A Mathematical and Theoretical•May 26, 2026•0 citations

Security of two-way continuous-variable quantum key distribution with source noise

Tianyi Wang, Song Yu, Yichen Zhang +2 more

We investigate the security of reverse reconciliation two-way continuous-variable quantum key distribution with source noise at both legitimate sides. Because the source noise originates from imperfect devices, we ascribe it to the legitimate sides rather than the eavesdropper. The trusted model consists of a thermal noise injected into a beam splitter. The expressions of secret key rate are derived against collective entangling cloner attacks for homodyne and heterodyne detections. Simulation results show that by applying the trusted model, the security bound of the reverse reconciliation two-way protocols can be tightened, while the advantage over one-way protocols still maintains.

Journal of Physics B Atomic Molecular and Optical Physics•Oct 15, 2014•4 citations

Security bound of continuous-variable quantum key distribution with discrete modulation

Yong Shen, Zou Hong-Xin, 国防科学技术大学理学院物理系 长沙 410073

Security of continuous-variable quantum key distribution with four-state protocol based on discrete modulation of noisy coherent states is analyzed. Combing discrete modulation and reverse reconciliation, this protocol can be used for long distance cryptography. There is a small difference between the state Alice sends in the discrete modulation protocol and the Gaussian modulation protocol, and it can be treated as excess noise and loss in the channel. As Alice cannot do a precise modulation, she will induce noise to the coherent state. We look this noise as the source noise and derive a lower bound to the secure key rate assuming the eavesdropper cannot benefit from the noise in the source. For avoiding the fast and random phase locking between the signal and local oscillator in experiment, we also analyze the security of four-state protocol using no-switching scheme.

Acta Physica Sinica•Jan 1, 2010•7 citations
The system's source noise affects the practical performance of discrete-modulated continuous-variable quantum key distribution. The good news: This noise exists inside the system and cannot be exploited by eavesdroppers, so it can be trusted. However, a lack of appropriate modeling leaves a security-key-rate gap, omitting this trusted noise. The authors propose a model for trusted source noise in the discrete-modulated protocol, successfully mitigating the negative impact of an imperfect source on system performance while maintaining security of the protocol, and thus promoting practical deployment.
As quantum key distribution becomes a mature technology, it appears clearly that some assumptions made in the security proofs cannot be justified in practical implementations. This might open the door to possible side-channel attacks. We examine several discrepancies between theoretical models and experimental setups in the case of continuous-variable quantum key distribution. We study in particular the impact of an imperfect modulation on the security of Gaussian protocols and show that approximating the theoretical Gaussian modulation with a discrete one is sufficient in practice. We also address the issue of properly calibrating the detection setup and in particular the value of the shot noise. Finally, we consider the influence of phase noise in the preparation stage of the protocol and argue that taking this noise into account can improve the secret key rate because this source of noise is not controlled by the eavesdropper.
Discrete-modulated continuous-variable quantum key distribution protocols are promising candidates for large-scale deployment due to the large technological overlap with deployed modern optical communication devices. The security of discrete modulation schemes has previously been analyzed in the ideal detector scenario in the asymptotic limit. In this work, we calculate asymptotic key rates against collective attacks in the trusted detector noise scenario. Our results show that we can thus cut out most of the effect of detector noise and obtain asymptotic key rates similar to those had we access to ideal detectors.
Discrete-modulated continuous-variable quantum key distribution offers significant practical deployment advantages due to its straightforward state preparation and high compatibility with coherent optical communication systems. However, security analysis and parameter estimation of discrete-modulated protocol are different with Gaussian-modulated protocols, which could cause different practical security problems. Herein, we investigate the amplitude-boosting attack against discrete-modulated continuous-variable quantum key distribution systems and assess its impact on system performance. Our findings reveal that this attack could cause overestimation of secret key rate perceived by Alice and Bob, thereby opening a security loophole, and the vulnerability could be severer than Gaussian modulation. Additionally, we summarize defensive countermeasures, marking a crucial step towards enhancing the practical security of discrete-modulated continuous-variable quantum key distribution.
Abstract Two-way continuous-variable quantum key distribution protocol, where the parties make a double use of the quantum channel, shows the general superadditivity in the security thresholds, which are proven to be higher than that of the classical one-way protocol. However, all existing security proofs for two-way protocols assume perfect source devices or a trusted source noise, which is hard to ensure in a practical system. In this paper, the effects of multiple source fluctuations on the security of the two-way protocol are proposed, where Eve may have access to the intensity fluctuation information with an arbitrary random distribution. This work is comprehensive of several practical scenarios, encompassing both ON and OFF configurations, with and without the assumption that trusted users can access the fluctuation information. The analysis shows that when the users have no fluctuation information, the intensity fluctuation effect in the ON configuration should be modeled as an additional thermal noise rather than being described by a beam splitter model as in the general one-way protocol. In addition, this untrusted noise is only related to the intensity fluctuation variance but has no relation to its distribution. Finally, the tagging idea is applied to the two-way protocol to obtain a conservative secure key.
We investigate the security of reverse reconciliation two-way continuous-variable quantum key distribution with source noise at both legitimate sides. Because the source noise originates from imperfect devices, we ascribe it to the legitimate sides rather than the eavesdropper. The trusted model consists of a thermal noise injected into a beam splitter. The expressions of secret key rate are derived against collective entangling cloner attacks for homodyne and heterodyne detections. Simulation results show that by applying the trusted model, the security bound of the reverse reconciliation two-way protocols can be tightened, while the advantage over one-way protocols still maintains.
Security of continuous-variable quantum key distribution with four-state protocol based on discrete modulation of noisy coherent states is analyzed. Combing discrete modulation and reverse reconciliation, this protocol can be used for long distance cryptography. There is a small difference between the state Alice sends in the discrete modulation protocol and the Gaussian modulation protocol, and it can be treated as excess noise and loss in the channel. As Alice cannot do a precise modulation, she will induce noise to the coherent state. We look this noise as the source noise and derive a lower bound to the secure key rate assuming the eavesdropper cannot benefit from the noise in the source. For avoiding the fast and random phase locking between the signal and local oscillator in experiment, we also analyze the security of four-state protocol using no-switching scheme.