Beating Classical Impossibility of Position Verification

Beating Classical Impossibility of Position Verification

Cybersecurity Seminars Online seminar
Thursday, 24 February 2022
12 pm - 1 pm (AEDT)

In this work, we initiate the study of position verification protocols with classical verifiers. Position verification is the central task for position-based cryptography, which aims to verify one’s geographical location in a cryptographically secure way.

Chandran et al. (SIAM J. Comput.'14) formally introduced the cryptographic task of position verification, where they also showed that it cannot be achieved by classical protocols. We identify that proofs of quantumness (and thus computational assumptions) are necessary for such position verification protocols. For the other direction, we adapt the proof of quantumness protocol by Brakerski et al. (FOCS'18) to instantiate such a position verification protocol. As a result, we achieve classically verifiable position verification assuming the quantum hardness of Learning with Errors.

For this talk, quantum background is not assumed. The speaker will mostly use the proof of quantumness protocol in a black-box way.

Based on a joint work with Jiahui Liu and Luowen Qian, "Beating Classical Impossibility of Position Verification", ITCS 22, QIP 22.

About the speaker

Qipeng Liu
Postdoc, Simons Institute for the Theory of Computing

Qipeng Liu is a Simons Quantum Postdoctoral Fellow, hosted by Shafi Goldwasser and Umesh Vazirani. He earned his Ph.D. degree at Princeton University in 2021, under the guidance of Professor Mark Zhandry. Qipeng's research interest is in quantum cryptography, including both post-quantum security and quantum protocols.

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