Improved Polar-code-based Efficient Post-processing Algorithm for Quantum Key Distribution

TL;DR

This paper introduces a polar-code-based post-processing algorithm for quantum key distribution that combines error correction and privacy amplification into a single step, significantly reducing delay and complexity while maintaining security.

Contribution

It proposes a novel polar code structure tailored for quantum key distribution, enabling synchronous error correction and privacy amplification, thus improving efficiency.

Findings

Reduces post-processing delay in quantum key distribution

Maintains reliable and secure communication conditions

Demonstrates effectiveness through simulation results

Abstract

Combined with one-time pad encryption scheme, quantum key distribution guarantees the unconditional security of communication in theory. However, error correction and privacy amplification in the post-processing phase of quantum key distribution result in high time delay, which limits the final secret key generation rate and the practicability of quantum key distribution systems. To alleviate this limitation, this paper proposes an efficient post-processing algorithm based on polar codes for quantum key distribution. In this algorithm, by analyzing the channel capacity of the main channel and the wiretap channel respectively under the Wyner's wiretap channel model, we design a codeword structure of polar codes, so that the error correction and privacy amplification could be completed synchronously in a single step. Through combining error correction and privacy amplification into one single step, this efficient post-processing algorithm reduces complexity of the system and lower the post-processing delay. Besides, the reliable and secure communicaiton conditions for this algorithm has been given in this paper. Simulation results show that this post-processing algorithm satisfies the reliable and secure communication conditions well.