# Biased decoy-state reference-frame-independent quantum key distribution

## TL;DR

This paper introduces a biased decoy-state reference-frame-independent quantum key distribution scheme that enhances key rate and transmission distance by reducing mismatched data, even with reference frame drift.

## Contribution

It proposes a novel biased basis assignment method for decoy-state RFI-QKD, improving performance over existing schemes under practical conditions.

## Key findings

- Significant increase in secret key rate
- Extended secure transmission distance
- Better performance compared to unbiased schemes

## Abstract

Without actively aligning the reference frames, the reference-frame-independent quantum key distribution (RFI-QKD) can generate secure keys even when the reference frames drift slowly. Here, we propose a new scheme on the decoy-state RFI-QKD, where the basis assignments of two legitimate parties are biased, reducing the fraction of mismatched-basis data. When accounting for statistical fluctuations under different misalignments of reference frames, we investigate the performance of biased decoy-state RFI-QKD with full parameter optimization. We also make a clear comparison between the new scheme with other practical schemes, e.g., unbiased decoy-state RFI-QKD and biased decoy-state BB84-QKD. Simulation results demonstrate that the new proposed biased decoy-state RFI-QKD can significantly improve the performance (secret key rate and secure transmission distance) of practical QKD systems.

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Source: https://tomesphere.com/paper/1703.03951