Security of a Continuous-Variable based Quantum Position Verification Protocol

TL;DR

This paper investigates a quantum position verification protocol using continuous-variable states, highlighting its security advantages and vulnerabilities, with practical implications for quantum communication systems.

Contribution

It introduces a new continuous-variable quantum position verification protocol and analyzes its security against different attack strategies.

Findings

Protocol is secure against unentangled attackers with low noise

Pre-shared EPR pairs can compromise the protocol

Coherent states offer practical advantages over discrete states

Abstract

In this work we study quantum position verification with continuous-variable quantum states. In contrast to existing discrete protocols, we present and analyze a protocol that utilizes coherent states and its properties. Compared to discrete-variable photonic states, coherent states offer practical advantages since they can be efficiently prepared and manipulated with current technology. We prove security of the protocol against any unentangled attackers via entropic uncertainty relations, showing that the adversary has more uncertainty than the honest prover about the correct response as long as the noise in the quantum channel is below a certain threshold. Additionally, we show that attackers who pre-share one continuous-variable EPR pair can break the protocol.