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Main Authors: Kim, Hyeonhak, Heo, Donghoe, Hong, Seokhie
Format: Preprint
Published: 2025
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Online Access:https://arxiv.org/abs/2508.00351
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author Kim, Hyeonhak
Heo, Donghoe
Hong, Seokhie
author_facet Kim, Hyeonhak
Heo, Donghoe
Hong, Seokhie
contents Quantum money is the cryptographic application of the quantum no-cloning theorem. It has recently been instantiated by Montgomery and Sharif (Asiacrypt '24) from class group actions on elliptic curves. In this work, we propose a concrete cryptanalysis by leveraging the efficiency of evaluating division polynomials with the coordinates of rational points, offering a speedup of O(log^4p) compared to the brute-force attack. Since our attack still requires exponential time, it remains impractical to forge a quantum banknote. Interestingly, due to the inherent properties of quantum money, our attack method also results in a more efficient verification procedure. Our algorithm leverages the properties of quadratic twists to utilize rational points in verifying the cardinality of the superposition of elliptic curves. We expect this approach to contribute to future research on elliptic-curve-based quantum cryptography.
format Preprint
id arxiv_https___arxiv_org_abs_2508_00351
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Cryptanalysis of Isogeny-Based Quantum Money with Rational Points
Kim, Hyeonhak
Heo, Donghoe
Hong, Seokhie
Cryptography and Security
Quantum money is the cryptographic application of the quantum no-cloning theorem. It has recently been instantiated by Montgomery and Sharif (Asiacrypt '24) from class group actions on elliptic curves. In this work, we propose a concrete cryptanalysis by leveraging the efficiency of evaluating division polynomials with the coordinates of rational points, offering a speedup of O(log^4p) compared to the brute-force attack. Since our attack still requires exponential time, it remains impractical to forge a quantum banknote. Interestingly, due to the inherent properties of quantum money, our attack method also results in a more efficient verification procedure. Our algorithm leverages the properties of quadratic twists to utilize rational points in verifying the cardinality of the superposition of elliptic curves. We expect this approach to contribute to future research on elliptic-curve-based quantum cryptography.
title Cryptanalysis of Isogeny-Based Quantum Money with Rational Points
topic Cryptography and Security
url https://arxiv.org/abs/2508.00351