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

IEEE Communications Letters

Security of Binary Modulated Continuous Variable Quantum Key Distribution Using Optimally Displaced Threshold Detection

Mufei Zhao, Renzhi Yuan, Julian Cheng, Shuai Han

Published Dec 30, 2020• 14 citations
Publisher

Abstract

Continuous variable quantum key distribution attracts increasing attention in recent years due to its potential high secret key rates and the compatibility with existing communication infrastructure. This letter derives the secret key rate for a binary modulated continuous variable quantum key distribution using an optimally displaced threshold detection and post-selection. To improve the secret key rate, we optimize the post selected area and the coherent amplitude for different transmission efficiency of the channel under different thermal noises. Both the individual and collective beamsplitter attacks are considered. Numerical results show that the secret key rate using the optimally displaced threshold detection can surpass that using the classical detection scheme under different transmission efficiencies and different thermal noises. Besides, more improvement on the secret key rate can be obtained when the transmission efficiency is low.

DOI
10.1109/lcomm.2020.3048266

Related papers

Security of Coherent-State Quantum Key Distribution Using Displacement Receiver

Mufei Zhao, Renzhi Yuan, Chen Feng +2 more

Continuous variable quantum key distribution (CV-QKD) protocol has drawn much attention due to its compatibility with existing optical communication systems. In this paper, we propose a quaternary modulated CV-QKD protocol using displacement receivers and adopt the post-selection scheme to overcome the ‘3dB limit’. We first establish the model of displacement receiver for discriminating quaternary modulated coherent signals in a realistic situation. The performance of non-adaptive displacement receiver and multi-stage feedforward receiver are both investigated under different noises and device imperfections. To improve the receiver performance, we numerically optimize the displacement operation and check the quantum advantage of the displacement receivers over the classical homodyne detection. Then we analyze the security of the proposed CV-QKD protocol. The secret key rate is derived for both types of displacement receivers under the collective beam splitting attack. We also optimize the transmitted signal photons for different channel transmission efficiencies under practical system constraints. Numerical results shed light on the practical application of displacement receivers in CV-QKD protocols. This includes evaluating the necessity of optimizing the displacement and incorporating the feedforward structure in a displacement receiver according to different practical system limitations. Moreover, under higher channel transmission efficiency and increased receiver noise level, a larger coherent amplitude is required for transmitting signals to attain the maximum secret key rate.

IEEE Journal on Selected Areas in Communications•Mar 22, 2024•7 citations

Towards Secure Coherent-State QKD with Practical Quantum Detection

Shuai Han, Mufei Zhao, Renzhi Yuan +2 more

Security analysis of continuous variable quantum key distribution (CV-QKD) remains a topic of extensive academic investigation. In this work, we propose a coherent-state CV-QKD protocol integrating a displacement-based quantum receiver and post-selection strategies. We establish a framework of the protocol under both individual and collective attacks, incorporating practical constraints such as noises and device imperfections. To enhance performance of the protocol, the postselection strategy and the transmitted signal power are optimized for different channel attenuation levels. Numerical results offer insights into the strategy of employing displacement receivers in CV-QKD protocols, revealing that larger transmitted signal power is required under low channel attenuation or severe receiver-side imperfections and noises to achieve higher the secret key rate.

Globecom•Dec 8, 2025•0 citations

Asymptotic security of binary modulated continuous-variable quantum key distribution under collective attacks

Zhao Yi-Bo, Matthias Heid, Johannes Rigas +1 more

We estimate a lower bound to the secret key rate of a binary modulated continuous variable quantum key distribution scheme. We consider the collective attack scenario with quantum channels that impose arbitrary noise on the exchanged signals. The analysis is done in the infinite key limit. Bob performs ideal homodyne measurements on the received states and the two honest parties employ a reverse reconciliation procedure in the classical postprocessing step of the protocol.

arXiv:0807.3751•Physical Review A•Jan 9, 2009•111 citations

Asymptotic security of discrete-modulation protocols for continuous-variable quantum key distribution

Eneet Kaur, Saikat Guha, Mark M. Wilde

We consider discrete-modulation protocols for continuous-variable quantum key distribution (CV-QKD) that employ a modulation constellation consisting of a finite number of coherent states and that use a homodyne- or a heterodyne-detection receiver. We establish a security proof for collective attacks in the asymptotic regime, and we provide a formula for an achievable secret-key rate. Previous works established security proofs for discrete-modulation CV-QKD protocols that use two or three coherent states. The main constituents of our approach include approximating a complex, isotropic Gaussian probability distribution by a finite-size Gauss-Hermite constellation, applying entropic continuity bounds, and leveraging previous security proofs for Gaussian-modulation protocols. As an application of our method, we calculate secret-key rates achievable over a lossy thermal bosonic channel. We show that the rates for discrete-modulation protocols approach the rates achieved by a Gaussian-modulation protocol as the constellation size is increased. For pure-loss channels, our results indicate that in the high-loss regime and for sufficiently large constellation size, the achievable key rates scale optimally, i.e., proportional to the channel's transmissivity.

arXiv:1901.10099•Physical Review A•Jan 15, 2021•52 citations

Security against Collective Attacks for a Continuous-Variable Quantum Key Distribution Protocol Using Homodyne Detection and Postselection

Ryo Namiki

We analyze the security against collective attacks for a homodyne-based continuous-variable quantum key distribution protocol using binary coherent states and postselection. We derive a lower bound of the secret key rate in an asymptotic scenario, and numerically optimize it for the case of a symmetric Gaussian channel.

arXiv:2205.11820•Journal of the Physical Society of Japan•Dec 2, 2022•2 citations

High-Rate Discrete-Modulated Continuous-Variable Quantum Key Distribution with Composable Security

Mingze Wu, Yan Pan, Junhui Li +8 more

Continuous-variable quantum key distribution holds the potential to generate high secret key rates, making it a prime candidate for high-rate metropolitan quantum network applications. However, despite these promising opportunities, the realization of high-rate continuous-variable quantum key distribution systems with composable security remains an elusive goal. Here, we report a discrete-modulated continuous-variable quantum key distribution system with a composable secret key rate of 18.93 Mbps against collective attacks over a 25-km fiber channel. This record-breaking rate is achieved through the probability-shaped 16 quadrature amplitude modulation-modulated protocol, which employs semidefinite programming to ensure its composable security. Furthermore, we have employed a fully digital and precise quantum signal processing technique to reduce excess noise to extremely low levels, thereby facilitating efficient broadband system operation. While ensuring low complexity and cost, our system achieves a performance advantage of over an order of magnitude compared to previous continuous-variable quantum key distribution systems, providing a promising solution for future deployment of quantum key distribution.

arXiv:2503.11431•Physical Review X•Apr 23, 2026•1 citation
Continuous variable quantum key distribution attracts increasing attention in recent years due to its potential high secret key rates and the compatibility with existing communication infrastructure. This letter derives the secret key rate for a binary modulated continuous variable quantum key distribution using an optimally displaced threshold detection and post-selection. To improve the secret key rate, we optimize the post selected area and the coherent amplitude for different transmission efficiency of the channel under different thermal noises. Both the individual and collective beamsplitter attacks are considered. Numerical results show that the secret key rate using the optimally displaced threshold detection can surpass that using the classical detection scheme under different transmission efficiencies and different thermal noises. Besides, more improvement on the secret key rate can be obtained when the transmission efficiency is low.
Continuous variable quantum key distribution (CV-QKD) protocol has drawn much attention due to its compatibility with existing optical communication systems. In this paper, we propose a quaternary modulated CV-QKD protocol using displacement receivers and adopt the post-selection scheme to overcome the ‘3dB limit’. We first establish the model of displacement receiver for discriminating quaternary modulated coherent signals in a realistic situation. The performance of non-adaptive displacement receiver and multi-stage feedforward receiver are both investigated under different noises and device imperfections. To improve the receiver performance, we numerically optimize the displacement operation and check the quantum advantage of the displacement receivers over the classical homodyne detection. Then we analyze the security of the proposed CV-QKD protocol. The secret key rate is derived for both types of displacement receivers under the collective beam splitting attack. We also optimize the transmitted signal photons for different channel transmission efficiencies under practical system constraints. Numerical results shed light on the practical application of displacement receivers in CV-QKD protocols. This includes evaluating the necessity of optimizing the displacement and incorporating the feedforward structure in a displacement receiver according to different practical system limitations. Moreover, under higher channel transmission efficiency and increased receiver noise level, a larger coherent amplitude is required for transmitting signals to attain the maximum secret key rate.
Security analysis of continuous variable quantum key distribution (CV-QKD) remains a topic of extensive academic investigation. In this work, we propose a coherent-state CV-QKD protocol integrating a displacement-based quantum receiver and post-selection strategies. We establish a framework of the protocol under both individual and collective attacks, incorporating practical constraints such as noises and device imperfections. To enhance performance of the protocol, the postselection strategy and the transmitted signal power are optimized for different channel attenuation levels. Numerical results offer insights into the strategy of employing displacement receivers in CV-QKD protocols, revealing that larger transmitted signal power is required under low channel attenuation or severe receiver-side imperfections and noises to achieve higher the secret key rate.
We consider discrete-modulation protocols for continuous-variable quantum key distribution (CV-QKD) that employ a modulation constellation consisting of a finite number of coherent states and that use a homodyne- or a heterodyne-detection receiver. We establish a security proof for collective attacks in the asymptotic regime, and we provide a formula for an achievable secret-key rate. Previous works established security proofs for discrete-modulation CV-QKD protocols that use two or three coherent states. The main constituents of our approach include approximating a complex, isotropic Gaussian probability distribution by a finite-size Gauss-Hermite constellation, applying entropic continuity bounds, and leveraging previous security proofs for Gaussian-modulation protocols. As an application of our method, we calculate secret-key rates achievable over a lossy thermal bosonic channel. We show that the rates for discrete-modulation protocols approach the rates achieved by a Gaussian-modulation protocol as the constellation size is increased. For pure-loss channels, our results indicate that in the high-loss regime and for sufficiently large constellation size, the achievable key rates scale optimally, i.e., proportional to the channel's transmissivity.
Continuous-variable quantum key distribution holds the potential to generate high secret key rates, making it a prime candidate for high-rate metropolitan quantum network applications. However, despite these promising opportunities, the realization of high-rate continuous-variable quantum key distribution systems with composable security remains an elusive goal. Here, we report a discrete-modulated continuous-variable quantum key distribution system with a composable secret key rate of 18.93 Mbps against collective attacks over a 25-km fiber channel. This record-breaking rate is achieved through the probability-shaped 16 quadrature amplitude modulation-modulated protocol, which employs semidefinite programming to ensure its composable security. Furthermore, we have employed a fully digital and precise quantum signal processing technique to reduce excess noise to extremely low levels, thereby facilitating efficient broadband system operation. While ensuring low complexity and cost, our system achieves a performance advantage of over an order of magnitude compared to previous continuous-variable quantum key distribution systems, providing a promising solution for future deployment of quantum key distribution.