Qudit-Based Measurement-Device-Independent Quantum Key Distribution Using Linear Optics

TL;DR

This paper introduces a feasible qudit-based measurement-device-independent quantum key distribution system using linear optics, unifying and extending secure QKD protocols to prevent detector side-channel attacks.

Contribution

It presents a new MDI-QKD protocol applicable to all provably secure qudit-based schemes, including RRDPS, with an experimental optical implementation based on entanglement swapping.

Findings

Proposes a universal MDI-QKD protocol for qudit schemes.

Demonstrates an optical implementation of entanglement swapping for MDI-QKD.

Shows all provably secure qudit-based QKD schemes can be made MDI.

Abstract

Measurement-device-independent (MDI) method is a way to solve all detector side-channel attacks in quantum key distribution (QKD). However, very little work has been done on experimentally feasible qudit-based MDI-QKD scheme although the famous (qudit-based) round-robin differential-phase-shift (RRDPS) scheme is vulnerable to attacks on uncharacterized detectors. Here we report a mother-of-all QKD protocol on which all provably secure qubit-based QKD schemes known to date including the RRDPS and the so-called Chau15 schemes are based. We also report an experimentally feasible MDI system via optical implementation of entanglement swapping based on a recent qudit teleportation proposal by Goyal et al. In this way, we show that all provably secure qudit-based QKD schemes discovered to date can be made MDI.