Practically secure quantum position verification

TL;DR

This paper proposes practically secure quantum position verification protocols that remain secure against realistic adversaries, requiring exponentially large entanglement to break, by integrating classical randomness into existing quantum protocols.

Contribution

It introduces modified QPV protocols with classical random oracles that enhance security without increasing quantum resource requirements.

Findings

Security is maintained against feasible adversaries

Cheating requires exponentially large entanglement

Protocols are practical with current quantum technology

Abstract

We discuss quantum position verification (QPV) protocols in which the verifiers create and send single-qubit states to the prover. QPV protocols using single-qubit states are known to be insecure against adversaries that share a small number of entangled qubits. We introduce QPV protocols that are practically secure: they only require single-qubit states from each of the verifiers, yet their security is broken if the adversaries share an impractically large number of shared entangled qubits. These protocols are a modification of known QPV protocols in which we include a classical random oracle without altering the amount of quantum resources needed by the verifiers. We present a cheating strategy that requires a number of entangled qubits shared among the adversaries that grows exponentially with the size of the classical input of the random oracle.