Loss-Tolerant Quantum Position Verification for Metropolitan Area Networks
Abstract
A spacetime seal, a cryptographic guarantee that a digital event has occurred at an approved location and time, can augment a digital signature with location attestation for legal, financial, and regulatory use cases. In adversarial settings any purely classical realization of such a seal can be spoofed. Quantum position verification (QPV) offers a physics-based solution, exploiting the no-cloning theorem and the no-signaling principle to certify a party's spacetime coordinates. While the feasibility of QPV has been recently shown via entanglement- and coherent light-based protocols, achieving loss tolerance for these schemes substantially increases implementation complexity at metropolitan scales. Here, we introduce and experimentally demonstrate a loss-tolerant QPV (LT-QPV) protocol whose security is independent of channel loss. We prove finite-size security against quantum polynomial-time entangled adversaries in the quantum random oracle model instantiated with cryptographically secure hash functions. Implemented entirely with commercial off-the-shelf components, our system certifies position within 22 minutes of net data collection time against a restricted adversary, with a clear path to real-time certification (<1s) with upgraded hardware. Our architecture, requiring only a single quantum verifier node alongside classical infrastructure, is naturally compatible with metropolitan-area quantum networks, establishing the foundations for scalable, physics-backed spacetime certification as a deployable service.
Related
- Arbitrarily Loss-Tolerant Quantum Position Verification in a Single Execution
- Two-Layer Verification for Fault-Tolerant Magic-State Preparation in High-Rate Quantum Codes
- Efficient multi-basis quantum position verification secure against generalized adversaries
- Breaking the Bounded Entanglement Barrier for Quantum Position Verification
- Fast verification of fault tolerant magic state preparation circuits with the CNOT + T gate set
BibTeX
@misc{kon2026losstolerant,
title = {{Loss-Tolerant Quantum Position Verification for Metropolitan Area Networks}},
author = {Wen Yu Kon and Niccolò Bigagli and Andrew Conrad and Taylor Shields and Fatih Kaleoglu and Ignatius William Primaatmaja and Alexander Craddock and RJ Pisani and Mael Flament and Jude Seeber and Omar Amer and Charles Lim and Xinhua Ling and Rob Otter and Kaushik Chakraborty and Mehdi Namazi},
howpublished = {arXiv},
year = {2026},
month = sep,
doi = {10.48550/arxiv.2609.23234},
eprint = {2609.23234},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2609.23234},
note = {CC BY 4.0},
}
RIS
TY - UNPB
TI - Loss-Tolerant Quantum Position Verification for Metropolitan Area Networks
AU - Wen Yu Kon
AU - Niccolò Bigagli
AU - Andrew Conrad
AU - Taylor Shields
AU - Fatih Kaleoglu
AU - Ignatius William Primaatmaja
AU - Alexander Craddock
AU - RJ Pisani
AU - Mael Flament
AU - Jude Seeber
AU - Omar Amer
AU - Charles Lim
AU - Xinhua Ling
AU - Rob Otter
AU - Kaushik Chakraborty
AU - Mehdi Namazi
PY - 2026
DA - 2026/09/19
PB - arXiv
DO - 10.48550/arxiv.2609.23234
UR - https://arxiv.org/abs/2609.23234
AB - A spacetime seal, a cryptographic guarantee that a digital event has occurred at an approved location and time, can augment a digital signature with location attestation for legal, financial, and regulatory use cases. In adversarial settings any purely classical realization of such a seal can be spoofed. Quantum position verification (QPV) offers a physics-based solution, exploiting the no-cloning theorem and the no-signaling principle to certify a party's spacetime coordinates. While the feasibility of QPV has been recently shown via entanglement- and coherent light-based protocols, achieving loss tolerance for these schemes substantially increases implementation complexity at metropolitan scales. Here, we introduce and experimentally demonstrate a loss-tolerant QPV (LT-QPV) protocol whose security is independent of channel loss. We prove finite-size security against quantum polynomial-time entangled adversaries in the quantum random oracle model instantiated with cryptographically secure hash functions. Implemented entirely with commercial off-the-shelf components, our system certifies position within 22 minutes of net data collection time against a restricted adversary, with a clear path to real-time certification (<1s) with upgraded hardware. Our architecture, requiring only a single quantum verifier node alongside classical infrastructure, is naturally compatible with metropolitan-area quantum networks, establishing the foundations for scalable, physics-backed spacetime certification as a deployable service.
ER -