QKD with finite resources: secret key rates via R\'enyi entropies

TL;DR

This paper derives a finite-resource secret key rate bound for QKD protocols using R\'enyi entropies, providing a computable estimate for the six-state protocol and demonstrating improved key rates.

Contribution

It introduces a new bound on QKD secret key rates based on R\'enyi entropies, applicable to finite resources and collective attacks, with practical estimations for the six-state protocol.

Findings

Derived a finite-resource key rate bound using R\'enyi entropies

Provided a computable estimate for the six-state protocol

Achieved improved key rates compared to previous bounds

Abstract

A realistic Quantum Key Distribution (QKD) protocol necessarily deals with finite resources, such as the number of signals exchanged by the two parties. We derive a bound on the secret key rate which is expressed as an optimization problem over R\'enyi entropies. Under the assumption of collective attacks by an eavesdropper, a computable estimate of our bound for the six-state protocol is provided. This bound leads to improved key rates in comparison to previous results.