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Short-block polar-coded reverse and direct reconciliation in CV-QKD

Short-block polar-coded reverse and direct reconciliation in CV-QKD
Short-block polar-coded reverse and direct reconciliation in CV-QKD

Continuous-variable quantum key distribution (CV-QKD) is a promising technique of supporting quantum-safe wireless networks in the emerging 6G era, mapping quantum information onto the amplitude or phase of electromagnetic waves. However, conventional CV-QKD reconciliation methods often assume ideal classical side-information channels, which is an unrealistic scenario in practical deployments. To address this critical challenge, we propose a novel protection scheme integrating Polar and low-density parity-check (LDPC) codes. Specifically, Polar codes safeguard quantum transmissions due to their superior performance for short block lengths, while LDPC codes robustly protect the classical side information exchanged over auxiliary classical channels. We further enhance the CV-QKD performance by harnessing a soft-decision Polar decoding method combined with protocols specifically tailored for reverse reconciliation (RR) and direct reconciliation (DR). In the RR scheme, conceived decoding complexity is strategically distributed: Polar decoding is performed by Alice, and LDPC decoding by Bob, hence significantly reducing the computational demands compared to traditional schemes where both decoding processes are invoked at a single node. Simulation results validate the effectiveness of our approach, demonstrating that Polar codes consistently outperform LDPC codes in quantum transmission scenarios having short block lengths under 512 bits. These findings emphasize the strong potential of Polar coding-assisted CV-QKD in achieving secure and efficient quantum-safe control information transmissions, paving the way for practical implementation in next-generation wireless networks.

Continuous-variable quantum key distribution (CV-QKD), Polar code, multidimensional reconciliation, secret key rate
2644-1330
2195-2209
Wang, Dingzhao
0385e0e5-7687-4d85-9714-5b431733cede
Liu, Xin
18299dbd-af76-4728-ac01-76eb68b2d76a
Xu, Chao
5710a067-6320-4f5a-8689-7881f6c46252
Ng, Soon Xin
e19a63b0-0f12-4591-ab5f-554820d5f78c
Hanzo, Lajos
66e7266f-3066-4fc0-8391-e000acce71a1
Wang, Dingzhao
0385e0e5-7687-4d85-9714-5b431733cede
Liu, Xin
18299dbd-af76-4728-ac01-76eb68b2d76a
Xu, Chao
5710a067-6320-4f5a-8689-7881f6c46252
Ng, Soon Xin
e19a63b0-0f12-4591-ab5f-554820d5f78c
Hanzo, Lajos
66e7266f-3066-4fc0-8391-e000acce71a1

Wang, Dingzhao, Liu, Xin, Xu, Chao, Ng, Soon Xin and Hanzo, Lajos (2025) Short-block polar-coded reverse and direct reconciliation in CV-QKD. IEEE Open Journal of Vehicular Technology, 6, 2195-2209. (doi:10.1109/OJVT.2025.3591417).

Record type: Article

Abstract

Continuous-variable quantum key distribution (CV-QKD) is a promising technique of supporting quantum-safe wireless networks in the emerging 6G era, mapping quantum information onto the amplitude or phase of electromagnetic waves. However, conventional CV-QKD reconciliation methods often assume ideal classical side-information channels, which is an unrealistic scenario in practical deployments. To address this critical challenge, we propose a novel protection scheme integrating Polar and low-density parity-check (LDPC) codes. Specifically, Polar codes safeguard quantum transmissions due to their superior performance for short block lengths, while LDPC codes robustly protect the classical side information exchanged over auxiliary classical channels. We further enhance the CV-QKD performance by harnessing a soft-decision Polar decoding method combined with protocols specifically tailored for reverse reconciliation (RR) and direct reconciliation (DR). In the RR scheme, conceived decoding complexity is strategically distributed: Polar decoding is performed by Alice, and LDPC decoding by Bob, hence significantly reducing the computational demands compared to traditional schemes where both decoding processes are invoked at a single node. Simulation results validate the effectiveness of our approach, demonstrating that Polar codes consistently outperform LDPC codes in quantum transmission scenarios having short block lengths under 512 bits. These findings emphasize the strong potential of Polar coding-assisted CV-QKD in achieving secure and efficient quantum-safe control information transmissions, paving the way for practical implementation in next-generation wireless networks.

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Accepted/In Press date: 18 July 2025
Published date: 21 July 2025
Keywords: Continuous-variable quantum key distribution (CV-QKD), Polar code, multidimensional reconciliation, secret key rate

Identifiers

Local EPrints ID: 504428
URI: http://eprints.soton.ac.uk/id/eprint/504428
ISSN: 2644-1330
PURE UUID: 6e5cdf03-e410-4437-97e2-71bdd89aca43
ORCID for Chao Xu: ORCID iD orcid.org/0000-0002-8423-0342
ORCID for Soon Xin Ng: ORCID iD orcid.org/0000-0002-0930-7194
ORCID for Lajos Hanzo: ORCID iD orcid.org/0000-0002-2636-5214

Catalogue record

Date deposited: 09 Sep 2025 17:18
Last modified: 11 Sep 2025 02:32

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Contributors

Author: Dingzhao Wang
Author: Xin Liu
Author: Chao Xu ORCID iD
Author: Soon Xin Ng ORCID iD
Author: Lajos Hanzo ORCID iD

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