Fully device-independent quantum key distribution using synchronous correlations

TL;DR

This paper introduces a new device-independent quantum key distribution protocol leveraging synchronous correlations, enhancing security and symmetry without preshared randomness, and addressing key loopholes in quantum cryptography.

Contribution

It presents a novel protocol based on synchronous correlations, closing the synchronicity and locality loopholes, and demonstrating self-testing properties for secure quantum communication.

Findings

Protocol achieves security without preshared randomness

Addresses and closes key loopholes in device-independent QKD

Demonstrates self-testing property for almost synchronous correlations

Abstract

We derive a device-independent quantum key distribution protocol based on synchronous correlations and their Bell inequalities. This protocol offers several advantages over other device-independent schemes including symmetry between the two users and no need for preshared randomness. We close a "synchronicity" loophole by showing that an almost synchronous correlation inherits the self-testing property of the associated synchronous correlation. We also pose a new security assumption that closes the "locality" (or "causality") loophole: an unbounded adversary with even a small uncertainty about the users' choice of measurement bases cannot produce any almost synchronous correlation that approximately maximally violates a synchronous Bell inequality.