Tight finite-key analysis for generalized high-dimensional quantum key distribution

TL;DR

This paper introduces a tight finite-key security analysis for high-dimensional quantum key distribution, enabling practical implementation with finite resources by bridging the gap between theory and experiment.

Contribution

It develops a novel finite-key analysis method based on key classification and uncertainty relations, applicable to generalized high-dimensional QKD protocols.

Findings

The analysis is tight and suitable for practical finite-resource scenarios.

It demonstrates the feasibility of high-dimensional QKD with finite signals.

The method improves security guarantees over previous infinite-key assumptions.

Abstract

Due to the capability of tolerating high error rate and generating more key bits per trial, high-dimensional quantum key distribution attracts wide interest. Despite great progresses in high-dimensional quantum key distribution, there are still some gaps between theory and experiment. One of these is that the security of the secret key heavily depends on the number of the emitted signals. So far, the existing security proofs are only suitable in the case with an infinite or unpractically large number of emitted signals. Here, by introducing the idea of "key classification" and developing relevant techniques based on the uncertainty relation for smooth entropies, we propose a tight finite-key analysis suitable for generalized high-dimensional quantum key distribution protocols. Benefitting from our theory, high-dimensional quantum key distribution protocols with finite resources become experimentally feasible.