Paper 2024/1844

KLaPoTi: An asymptotically efficient isogeny group action from 2-dimensional isogenies

Lorenz Panny, Technische Universität München, Germany
Christophe Petit, Université libre de Bruxelles, Belgium, University of Birmingham, UK
Miha Stopar, Université libre de Bruxelles, Belgium, Ethereum Foundation
Abstract

We construct and implement an efficient post-quantum commutative cryptographic group action based on combining the SCALLOP framework for group actions from isogenies of oriented elliptic curves on one hand with the recent Clapoti method for polynomial-time evaluation of the CM group action on elliptic curves on the other. We take advantage of the very attractive performance of $(2^e, 2^e)$-isogenies between products of elliptic curves in the theta coordinate system. To successfully apply Clapoti in dimension $2$, it is required to resolve a particular quadratic diophantine norm equation, for which we employ a slight variant of the KLPT algorithm. Our work marks the first practical instantiation of the CM group action for which both the setup as well as the online phase can be computed in (heuristic) polynomial time.

Metadata
Available format(s)
PDF
Category
Public-key cryptography
Publication info
Preprint.
Keywords
post-quantumgroup actionisogeniesquaternions
Contact author(s)
lorenz panny @ tum de
christophe f petit @ gmail com
stopar miha @ gmail com
History
2024-11-11: approved
2024-11-10: received
See all versions
Short URL
https://ia.cr/2024/1844
License
Creative Commons Attribution
CC BY

BibTeX

@misc{cryptoeprint:2024/1844,
      author = {Lorenz Panny and Christophe Petit and Miha Stopar},
      title = {{KLaPoTi}: An asymptotically efficient isogeny group action from 2-dimensional isogenies},
      howpublished = {Cryptology {ePrint} Archive, Paper 2024/1844},
      year = {2024},
      url = {https://eprint.iacr.org/2024/1844}
}
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