Ryo Ohashi

13 papers C 1Journal 9Unranked 3
YearRankTypeTitle / Venue / Authors
2026 — conf
A Collision Attack on the LTZ Hash Function Based on a Conjecture on Supersingular Non-superspecial Isogeny Graphs of Dimension 2.
PQCrypto (2)
Ryo Ohashi, Hiroshi Onuki
2026 J jnl
Superspecial genus-4 double covers of elliptic curves.
J. Symb. Comput.
Takumi Ogasawara, Ryo Ohashi, Kosuke Sakata, Shushi Harashita
2025 J jnl
A collision attack on the LTZ hash function based on a conjecture on supersingular non-superspecial isogeny graphs of dimension 2.
IACR Cryptol. ePrint Arch.
Ryo Ohashi, Hiroshi Onuki
2025 — conf
An Efficient Collision Attack on Castryck-Decru-Smith's Hash Function.
PQCrypto (2)
Ryo Ohashi, Hiroshi Onuki
2025 — conf
Efficient Theta-Based Algorithms for Computing (ℓ , ℓ )-Isogenies on Kummer Surfaces for Arbitrary Odd ℓ.
PQCrypto (2)
Ryo Yoshizumi, Hiroshi Onuki, Ryo Ohashi, Momonari Kudo, Koji Nuida
2024 J jnl
An efficient collision attack on Castryck-Decru-Smith's hash function.
IACR Cryptol. ePrint Arch.
Ryo Ohashi, Hiroshi Onuki
2024 J jnl
Efficient theta-based algorithms for computing (ℓ, ℓ)-isogenies on Kummer surfaces for arbitrary odd ℓ.
IACR Cryptol. ePrint Arch.
Ryo Yoshizumi, Hiroshi Onuki, Ryo Ohashi, Momonari Kudo, Koji Nuida
2024 J jnl
On the Rosenhain forms of superspecial curves of genus two.
Finite Fields Their Appl.
Ryo Ohashi
2023 J jnl
Computing superspecial hyperelliptic curves of genus 4 with automorphism group properly containing the Klein 4-group.
CoRR
Ryo Ohashi, Momonari Kudo
2022 C conf
Fast Enumeration of Superspecial Hyperelliptic Curves of Genus 4 with Automorphism Group V
WAIFI
Ryo Ohashi, Momonari Kudo, Shushi Harashita
2022 J jnl
Maximality of Ciani curves over finite fields.
Finite Fields Their Appl.
Ryo Ohashi
2018 J jnl
Finite actions on the 2-sphere, the projective plane and I-bundles over the projective plane.
Ars Math. Contemp.
John Kalliongis, Ryo Ohashi
2008 J jnl
The Rational Homology Group of Out(
Exp. Math.
Ryo Ohashi