Simple rate-adaptive LDPC coding for quantum key distribution

TL;DR

This paper introduces a simple, rate-adaptive LDPC coding method for quantum key distribution that improves reconciliation efficiency and throughput, addressing the bottleneck in post-processing.

Contribution

It proposes a novel, easily implementable rate-adaptive LDPC coding approach for QKD reconciliation, differing from existing puncturing and shortening methods.

Findings

Simulated the proposed LDPC approach showing improved efficiency

Provided a measure for optimal LDPC parameter selection based on error rates

Demonstrated the approach's potential to enhance QKD post-processing throughput

Abstract

Although quantum key distribution (QKD) comes from the development of quantum theory, the implementation of a practical QKD system does involve a lot of classical process, such as key reconciliation and privacy amplification, which is called post-processing. Post-processing has been a crucial element to high speed QKD systems, even the bottleneck of it because of its relatively high time consumption. Low density parity check (LDPC) is now becoming a promising approach of overcoming the bottleneck due to its good performance in processing throughput. In this article we propose and simulate an easily implemented but efficiently rate-adaptive LDPC coding approach of reconciliation, different from the previously proposed puncturing- and shortening-based approach. We also give a measure for choosing the optimal LDPC parameter for our rate-adaptive approach according to error rates.