Paper 2026/215 Original: eprint.iacr.org/2026/215 ↗

Endomorphisms via splittings

Sabrina Kunzweiler
Min-Yi Shen
Abstract

One of the fundamental hardness assumptions underlying isogeny-based cryptography is the problem of finding a non-trivial endomorphism of a given supersingular elliptic curve. We show that this problem is related to the problem of finding a good splitting of a principally polarized superspecial abelian surface. We provide formal security reductions, as well as a proof-of-concept implementation of an algorithm to compute endomorphisms of elliptic curves by solving the splitting problem.

Metadata
Available format(s)
PDF
Category
Attacks and cryptanalysis
Publication info
Preprint.
History
2026-02-12: last updated
2026-02-10: published
Short URL
https://ia.cr/2026/215
License
https://creativecommons.org/licenses/by/4.0/

BibTeX

@misc{cryptoeprint:2026/215,
      author = {Sabrina Kunzweiler and Min-Yi Shen},
      title = {Endomorphisms via splittings},
      howpublished = {Cryptology {ePrint} Archive, Paper 2026/215},
      year = {2026},
      url = {https://eprint.iacr.org/2026/215}
}
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