Device-independent quantum key distribution based on Bell inequalities with more than two inputs and two outputs

TL;DR

This paper introduces two new device-independent quantum key distribution protocols utilizing Bell inequalities with more than two inputs and outputs, potentially reducing detection efficiency requirements for practical implementation.

Contribution

It proposes novel DI-QKD protocols based on complex Bell inequalities, advancing the feasibility of secure quantum communication.

Findings

Protocols require lower detection efficiency with more complex Bell inequalities

Security relies on Bell inequalities with more than two inputs and outputs

Potential for improved practical DI-QKD implementations

Abstract

Device-independent quantum key distribution (DI-QKD) offers the strongest form of security against eavesdroppers bounded by the laws of quantum mechanics. However, a practical implementation is still pending due to the requirement of combinations of visibility and detection efficiency that are beyond those possible with current technology. This mismatch motivates the search for DI-QKD protocols that can close the gap between theoretical and practical security. In this work, we present two DI-QKD protocols whose security relies on Bell inequalities with more than two inputs and two outputs. We show that, for maximally entangled states and perfect visibility, a protocol based on a Bell inequality with three inputs and four outputs requires a slightly lower detection efficiency than the protocols based on Bell inequalities with two inputs and two outputs.