Practical Position-Based Quantum Cryptography

TL;DR

This paper introduces a new class of quantum position verification protocols and demonstrates that certain existing schemes are vulnerable to advanced attacks, while proposing a new protocol with improved security features.

Contribution

The paper presents a novel attack method based on the Clifford hierarchy and introduces the Interleaved Product protocol for position verification with enhanced security.

Findings

Clifford hierarchy-based attacks outperform previous strategies on practical protocols.

The Interleaved Product protocol involves only single-qubit states for position verification.

The best known attacks on the new protocol have exponential complexity in classical bits.

Abstract

We study a general family of quantum protocols for position verification and present a new class of attacks based on the Clifford hierarchy. These attacks outperform current strategies based on port-based teleportation for a large class of practical protocols. We then introduce the Interleaved Product protocol, a new scheme for position verification involving only the preparation and measurement of single-qubit states for which the best available attacks have a complexity exponential in the number of classical bits transmitted.