Continuous-variable Quantum Position Verification secure against entangled attackers

Rene Allerstorfer, Llorenç Escolà-Farràs, Arpan Akash Ray, Boris Skoric, Florian Speelman

Research output: Working paperPreprintProfessional

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Abstract

Motivated by the fact that coherent states may offer practical advantages it was recently shown that a continuous-variable (CV) quantum position verification (QPV) protocol using coherent states could be securely implemented if and only if attackers do not pre-share any entanglement. In the discrete-variable (DV) analogue of that protocol it was shown that modifying how the classical input information is sent from the verifiers to the prover leads to a favourable scaling in the resource requirements for a quantum attack. In this work, we show that similar conclusions can be drawn for CV-QPV. By adding extra classical information of size $n$ to a CV-QPV protocol, we show that the protocol, which uses a coherent state and classical information, remains secure, even if the quantum information travels arbitrarily slow, against attackers who pre-share CV (entangled) states with a linear (in $n$) cutoff at the photon number. We show that the protocol remains secure for certain attenuation and excess noise.
Original languageUndefined
Publication statusPublished - 22 Apr 2024

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