Weak randomness in device independent quantum key distribution and the advantage of using high dimensional entanglement

TL;DR

This paper investigates how weak randomness affects device independent quantum key distribution security and demonstrates that high-dimensional entanglement can enhance robustness against such weaknesses.

Contribution

It introduces a detailed analysis of the impact of weak randomness on security and shows that high-dimensional entanglement improves security robustness in these protocols.

Findings

Weak randomness can completely compromise security with small test samples.

Combining attack strategies can breach security even with larger test samples.

High-dimensional entanglement reduces vulnerability to weak randomness.

Abstract

We show that in device independent quantum key distribution protocols the privacy of randomness is of crucial importance. For sublinear test sample sizes even the slightest guessing probability by an eavesdropper will completely compromise security. We show that a combined attack exploiting test sample and measurement choices compromises the security even with a linear size test sample and otherwise device independent security considerations. We explicitly derive the sample size needed to retrieve security as a function of the randomness quality. We demonstrate that exploiting features of genuinely higher dimensional systems one can reduce this weakness and provide device independent security more robust against weak randomness sources.