Security of a High Dimensional Two-Way Quantum Key Distribution Protocol

TL;DR

This paper analyzes the security of a high-dimensional two-way quantum key distribution protocol, demonstrating its potential advantages and providing an information-theoretic security assessment in finite-key scenarios.

Contribution

It introduces a high-dimensional variant of the Ping Pong protocol and performs a comprehensive security analysis applicable to two-way quantum communication protocols.

Findings

High-dimensional states offer benefits in two-way QKD.

Security analysis in finite-key setting is achieved.

Methods are applicable to other two-way QKD protocols.

Abstract

Two-way quantum key distribution protocols utilize bi-directional quantum communication to establish a shared secret key. Due to the increased attack surface, security analyses remain challenging. Here we investigate a high-dimensional variant of the Ping Pong protocol and perform an information theoretic security analysis in the finite-key setting. Our methods may be broadly applicable to other QKD protocols, especially those relying on two-way channels. Along the way, we show some fascinating benefits to high-dimensional quantum states applied to two-way quantum communication.