Device-Independent Quantum Key Distribution with Local Bell Test

TL;DR

This paper introduces a new device-independent quantum key distribution protocol that performs the Bell test locally within Alice's lab, effectively overcoming the detection loophole caused by lossy quantum channels.

Contribution

It proposes a novel DIQKD protocol combining entropic uncertainty and local CHSH testing, eliminating the need for Bell violation across the channel.

Findings

The protocol avoids detection loopholes caused by channel losses.

It enables secure DIQKD with local Bell tests.

The approach enhances practical security in quantum communication.

Abstract

Device-independent quantum key distribution (DIQKD) in its current design requires a violation of Bell's inequality between two honest parties, Alice and Bob, who are connected by a quantum channel. However, in reality, quantum channels are lossy, and this can be exploited for attacks based on the detection loophole. Here, we propose a novel approach to DIQKD that overcomes this limitation. In particular, based on a combination between an entropic uncertainty relation and the Clauser-Horne-Shimony-Holt (CHSH) test, we design a DIQKD protocol where the CHSH test is carried out entirely in Alice's laboratory. Thus the loophole caused by channel losses is avoided.