Paper 2023/317

The special case of cyclotomic fields in quantum algorithms for unit groups

Razvan Barbulescu, Centre National de la Recherche Scientifique
Adrien Poulalion, Alice and Bob, Corps des Mines
Abstract

Unit group computations are a cryptographic primitive for which one has a fast quantum algorithm, but the required number of qubits is $\tilde{O}(m^5)$. In this work we propose a modification of the algorithm for which the number of qubits is $\tilde{O}(m^2)$ in the case of cyclotomic fields. Moreover, under a recent conjecture on the size of the class group of $\mathbb{Q}(\zeta_m+\zeta_m^{-1})$, the quantum algorithms is much simpler because it is a hidden subgroup problem (HSP) algorithm rather than its error estimation counterpart: continuous hidden subgroup problem (CHSP). We also discuss the (minor) speed-up obtained when exploiting Galois automorphisms thnaks to the Buchmann-Pohst algorithm over $\mathcal{O}_K$-lattices.

Metadata
Available format(s)
PDF
Category
Attacks and cryptanalysis
Publication info
Preprint.
Keywords
unit groupsquantum algorithmslatticescyclotomic fieldscyclotomic units
Contact author(s)
adrien poulalion @ mines org
History
2023-03-03: approved
2023-03-03: received
See all versions
Short URL
https://ia.cr/2023/317
License
Creative Commons Attribution
CC BY

BibTeX

@misc{cryptoeprint:2023/317,
      author = {Razvan Barbulescu and Adrien Poulalion},
      title = {The special case of cyclotomic fields in quantum algorithms for unit groups},
      howpublished = {Cryptology {ePrint} Archive, Paper 2023/317},
      year = {2023},
      url = {https://eprint.iacr.org/2023/317}
}
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