scholarly journals Impact of receiver imbalances on the security of continuous variables quantum key distribution

2021 ◽  
Vol 8 (1) ◽  
Author(s):  
Daniel Pereira ◽  
Margarida Almeida ◽  
Margarida Facão ◽  
Armando N. Pinto ◽  
Nuno A. Silva
Keyword(s):  
Communication Network ◽  
Quantum Key Distribution ◽  
Key Distribution ◽  
Continuous Variable ◽  
Continuous Variables ◽  
Security Risk ◽  
Channel Parameters ◽  
The Impact

AbstractContinuous-variable quantum key distribution (CV-QKD) provides a theoretical unconditionally secure solution to distribute symmetric keys among users in a communication network. However, the practical devices used to implement these systems are intrinsically imperfect, and, as a result, open the door to eavesdropper attacks. In this work, we show the impact of receiver device imperfections on the estimated channel parameters, performance and security of a CV-QKD system. The presented results show that, due to the erroneously estimated channel parameters, non-monitored imbalances can pose a security risk or even reduce the system’s performance. Our results show the importance of monitoring these imbalances and hint at the possibility of compensating for some receiver imbalances by tuning other components.

scholarly journals Continuous-Variable Quantum Key Distribution Based on Heralded Hybrid Linear Amplifier with a Local Local Oscillator

Entropy ◽  
2021 ◽  
Vol 23 (11) ◽  
pp. 1395
Author(s):  
Yin Li ◽  
Yijun Wang ◽  
Yun Mao ◽  
Weishao Peng ◽  
Di Jin ◽  
...  
Keyword(s):  
Quantum Key Distribution ◽  
Signal To Noise Ratio ◽  
Key Distribution ◽  
Local Oscillator ◽  
High Gain ◽  
Continuous Variable ◽  
Local Oscillation ◽  
Linear Amplifier ◽  
Fine Control ◽  
The Impact

An improved continuous variable quantum key distribution (CVQKD) approach based on a heralded hybrid linear amplifier (HLA) is proposed in this study, which includes an ideal deterministic linear amplifier and a probabilistic noiseless linear amplifier. The CVQKD, which is based on an amplifier, enhances the signal-to-noise ratio and provides for fine control between high gain and strong noise reduction. We focus on the impact of two types of optical amplifiers on system performance: phase sensitive amplifiers (PSA) and phase insensitive amplifiers (PIA). The results indicate that employing amplifiers, local local oscillation-based CVQKD systems can enhance key rates and communication distances. In addition, the PIA-based CVQKD system has a broader application than the PSA-based system.

Implementation of continuous variable quantum cryptography in optical fibres using a go-&-return configuration

2006 ◽  
Vol 6 (4&5) ◽  
pp. 326-335
Author(s):  
M. Legré ◽  
H. Zbinden ◽  
N. Gisin
Keyword(s):  
Quantum Cryptography ◽  
Quantum Key Distribution ◽  
Key Distribution ◽  
Continuous Variable ◽  
Optical Fibres ◽  
Continuous Variables ◽  
Phase Fluctuations ◽  
Degree Of Stability ◽  
Set Up ◽  
High Degree

We demonstrate an implementation of quantum key distribution with continuous variables based on a go-&-return configuration over distances up to 14km. This configuration leads to self-compensation of polarisation and phase fluctuations. We observe a high degree of stability of our set-up over many hours.

scholarly journals CONTINUOUS VARIABLE QUANTUM KEY DISTRIBUTION USING POLARIZED COHERENT STATES

2006 ◽  
Vol 20 (11n13) ◽  
pp. 1287-1296 ◽  
Author(s):  
A. VIDIELLA-BARRANCO ◽  
L. F. M. BORELLI
Keyword(s):  
Quantum Key Distribution ◽  
Coherent States ◽  
Key Distribution ◽  
Continuous Variable ◽  
Stokes Parameters ◽  
Continuous Variables ◽  
Commuting Operators ◽  
Incoming Beam ◽  
Ideal Situation ◽  
Quantum Counterpart

We discuss a continuous variables method of quantum key distribution employing strongly polarized coherent states of light. The key encoding is performed using the variables known as Stokes parameters, rather than the field quadratures. Their quantum counterpart, the Stokes operators Ŝi ( i =1,2,3), constitute a set of non-commuting operators, being the precision of simultaneous measurements of a pair of them limited by an uncertainty-like relation. Alice transmits a conveniently modulated two-mode coherent state, and Bob randomly measures one of the Stokes parameters of the incoming beam. After performing reconciliation and privacy amplification procedures, it is possible to distill a secret common key. We also consider a non-ideal situation, in which coherent states with thermal noise, instead of pure coherent states, are used for encoding.

scholarly journals Improving Eight-State Continuous Variable Quantum Key Distribution by Applying Photon Subtraction

2019 ◽  
Vol 9 (7) ◽  
pp. 1333 ◽  
Author(s):  
Qingquan Peng ◽  
Xiaodong Wu ◽  
Ying Guo
Keyword(s):  
Quantum Key Distribution ◽  
Single Photon ◽  
Key Distribution ◽  
Continuous Variable ◽  
Quantum States ◽  
Continuous Variables ◽  
Subtraction Method ◽  
Photon Subtraction ◽  
Channel Loss ◽  
Simulation Results

We propose a new method to effectively improve the performance of a quantum key distribution with eight-state continuous variables by the photon subtraction method. This operation is effective in increasing and distilling Gaussian entanglement between quantum states, and can be easily realized by existing technology. Simulation results show that the channel-loss tolerance of the eight-state continuous variable quantum key distribution (CVQKD) protocol can be extended by the appropriate photon subtraction algorithm; namely, single-photon subtraction.

Noise-enhanced CVQKD with untrusted source

2017 ◽  
Vol 31 (16) ◽  
pp. 1750143 ◽  
Author(s):  
Xiaoqun Wang ◽  
Chunhui Huang
Keyword(s):  
Quantum Key Distribution ◽  
Additive Noise ◽  
Key Distribution ◽  
Continuous Variable ◽  
Excess Noise ◽  
Transmission Distance ◽  
Simulation Results ◽  
The Impact ◽  
Maximum Transmission

The performance of one-way and two-way continuous variable quantum key distribution (CVQKD) protocols can be increased by adding some noise on the reconciliation side. In this paper, we propose to add noise at the reconciliation end to improve the performance of CVQKD with untrusted source. We derive the key rate of this case and analyze the impact of the additive noise. The simulation results show that the optimal additive noise can improve the performance of the system in terms of maximum transmission distance and tolerable excess noise.

scholarly journals Quantum-to-the-Home: Achieving Gbits/s Secure Key Rates via Commercial Off-the-Shelf Telecommunication Equipment

2017 ◽  
Vol 2017 ◽  
pp. 1-10 ◽  
Author(s):  
Rameez Asif ◽  
William J. Buchanan
Keyword(s):  
Quantum Key Distribution ◽  
High Performance ◽  
Copper Wire ◽  
Digital Signal ◽  
Key Distribution ◽  
Continuous Variable ◽  
Operating Conditions ◽  
Smooth Transition ◽  
Data Traffic ◽  
The Impact

There is current significant interest in Fiber-to-the-Home (FTTH) networks, that is, end-to-end optical connectivity. Currently, it may be limited due to the presence of last-mile copper wire connections. However, in near future, it is envisaged that FTTH connections will exist, and a key offering would be the possibility of optical encryption that can best be implemented using Quantum Key Distribution (QKD). However, it is very important that the QKD infrastructure is compatible with the already existing networks for a smooth transition and integration with the classical data traffic. In this paper, we report the feasibility of using off-the-shelf telecommunication components to enable high performance Continuous Variable-Quantum Key Distribution (CV-QKD) systems that can yield secure key rates in the range of 100 Mbits/s under practical operating conditions. Multilevel phase modulated signals (m-PSK) are evaluated in terms of secure key rates and transmission distances. The traditional receiver is discussed, aided by the phase noise cancellation based digital signal processing module for detecting the complex quantum signals. Furthermore, we have discussed the compatibility of multiplexers and demultiplexers for wavelength division multiplexed Quantum-to-the-Home (QTTH) network and the impact of splitting ratio is analyzed. The results are thoroughly compared with the commercially available high-cost encryption modules.

scholarly journals Secret Key Rate Adaption for Multicarrier Continuous-Variable Quantum Key Distribution

2019 ◽  
Vol 1 (1) ◽  
Author(s):  
Laszlo Gyongyosi ◽  
Sandor Imre
Keyword(s):  
Error Rate ◽  
Quantum Key Distribution ◽  
Key Distribution ◽  
Continuous Variable ◽  
Continuous Variables ◽  
Secret Key ◽  
Computational Tools ◽  
Minimal Error ◽  
Iterative Error

Abstract A multicarrier continuous-variable quantum key distribution (CVQKD) protocol uses Gaussian subcarrier quantum continuous variables (CVs) for the transmission. Here, we define an iterative error-minimizing secret key adaption method for multicarrier CVQKD. The proposed method allows for the parties to reach a given target secret key rate with minimized error rate through the Gaussian sub-channels by a sub-channel adaption procedure. The adaption algorithm iteratively determines the optimal transmit conditions to achieve the target secret key rate and the minimal error rate over the sub-channels. The solution requires no complex calculations or computational tools, allowing for easy implementation for experimental scenarios.

scholarly journals An FPGA-Based LDPC Decoder With Ultra-Long Codes for Continuous-Variable Quantum Key Distribution

IEEE Access ◽  
2021 ◽  
Vol 9 ◽  
pp. 47687-47697
Author(s):  
Shen-Shen Yang ◽  
Jian-Qiang Liu ◽  
Zhen-Guo Lu ◽  
Zeng-Liang Bai ◽  
Xu-Yang Wang ◽  
...  
Keyword(s):  
Quantum Key Distribution ◽  
Key Distribution ◽  
Continuous Variable ◽  
Ldpc Decoder

scholarly journals A novel error correction protocol for continuous variable quantum key distribution

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Kadir Gümüş ◽  
Tobias A. Eriksson ◽  
Masahiro Takeoka ◽  
Mikio Fujiwara ◽  
Masahide Sasaki ◽  
...  
Keyword(s):  
Error Correction ◽  
Quantum Key Distribution ◽  
Ldpc Codes ◽  
Key Distribution ◽  
Continuous Variable ◽  
Early Termination ◽  
Parity Check ◽  
Secret Key ◽  
Ldpc Decoder ◽  
And Performance

AbstractReconciliation is a key element of continuous-variable quantum key distribution (CV-QKD) protocols, affecting both the complexity and performance of the entire system. During the reconciliation protocol, error correction is typically performed using low-density parity-check (LDPC) codes with a single decoding attempt. In this paper, we propose a modification to a conventional reconciliation protocol used in four-state protocol CV-QKD systems called the multiple decoding attempts (MDA) protocol. MDA uses multiple decoding attempts with LDPC codes, each attempt having fewer decoding iteration than the conventional protocol. Between each decoding attempt we propose to reveal information bits, which effectively lowers the code rate. MDA is shown to outperform the conventional protocol in regards to the secret key rate (SKR). A 10% decrease in frame error rate and an 8.5% increase in SKR are reported in this paper. A simple early termination for the LDPC decoder is also proposed and implemented. With early termination, MDA has decoding complexity similar to the conventional protocol while having an improved SKR.

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