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arXiv · 2301.09236

On the (Im)plausibility of Public-Key Quantum Money from Collision-Resistant Hash Functions

Prabhanjan Ananth·Zihan Hu·Henry Yuen
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Abstract

Public-key quantum money is a cryptographic proposal for using highly entangled quantum states as currency that is publicly verifiable yet resistant to counterfeiting due to the laws of physics. Despite significant interest, constructing provably-secure public-key quantum money schemes based on standard cryptographic assumptions has remained an elusive goal. Even proposing plausibly-secure candidate schemes has been a challenge. These difficulties call for a deeper and systematic study of the structure of public-key quantum money schemes and the assumptions they can be based on. Motivated by this, we present the first black-box separation of quantum money and cryptographic primitives. Specifically, we show that collision-resistant hash functions cannot be used as a black-box to construct public-key quantum money schemes where the banknote verification makes classical queries to the hash function. Our result involves a novel combination of state synthesis techniques from quantum complexity theory and simulation techniques, including Zhandry's compressed oracle technique.

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Prabhanjan Ananth, Zihan Hu, Henry Yuen. 2023-01-23. On the (Im)plausibility of Public-Key Quantum Money from Collision-Resistant Hash Functions. https://arxiv.org/abs/2301.09236

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