Faster CGL Hash Function via Reduced Backtracking Checks.

Hiroshi Onuki https://orcid.org/0000-0002-0202-8918

Shota Inoue Yusuke Aikawa Tsuyoshi Takagi Hiroshi Onuki Faster CGL Hash Function via Reduced Backtracking Checks. 2026 147-155 109 IEICE Trans. Fundam. Electron. Commun. Comput. Sci. 3 https://doi.org/10.1587/transfun.2025cip0002 db/journals/ieiceta/ieiceta109.html#InoueATO26 streams/journals/ieiceta

Kohei Nakagawa Hiroshi Onuki SQIsign2DPush: Faster Signature Scheme Using 2-Dimensional Isogenies. EUROCRYPT (4) 2026 511-540 conf/eurocrypt/2026-4 https://doi.org/10.1007/978-3-032-25327-9_18 db/conf/eurocrypt/eurocrypt2026-4.html#NakagawaO26 streams/conf/eurocrypt Kohei Nakagawa Hiroshi Onuki Attacks on PRISM-id via Torsion over Small Extension Fields. PKC (1) 2026 480-509 conf/pkc/2026-1 https://doi.org/10.1007/978-3-032-26731-3_16 db/conf/pkc/pkc2026-1.html#NakagawaO26 streams/conf/pkc Ryo Ohashi Hiroshi Onuki A Collision Attack on the LTZ Hash Function Based on a Conjecture on Supersingular Non-superspecial Isogeny Graphs of Dimension 2. PQCrypto (2) 2026 377-408 conf/pqcrypto/2026-2 https://doi.org/10.1007/978-3-032-22698-3_12 db/conf/pqcrypto/pqcrypto2026-2.html#OhashiO26 streams/conf/pqcrypto

Masaomi Shibata Hiroshi Onuki Tsuyoshi Takagi Radical 3-isogenies for the ideal class group actions on (2, ε)-structures. 576 2026 2026 IACR Cryptol. ePrint Arch. https://eprint.iacr.org/2026/576 db/journals/iacr/iacr2026.html#ShibataOT26

Tomoki Moriya Hiroshi Onuki Yusuke Aikawa Tsuyoshi Takagi Lower Bounds of Costs of 3-Isogenies Formulas in the Framework of Generalized Montgomery Coordinates. 245-264 2025 CASC https://doi.org/10.1007/978-3-032-09645-6_14 conf/casc/2025 db/conf/casc/casc2025.html#MoriyaOAT25 streams/conf/casc Ryo Yoshizumi Hiroshi Onuki Ryo Ohashi Momonari Kudo Koji Nuida Efficient Theta-Based Algorithms for Computing (ℓ , ℓ )-Isogenies on Kummer Surfaces for Arbitrary Odd ℓ. 3-37 2025 PQCrypto (2) https://doi.org/10.1007/978-3-031-86602-9_1 conf/pqcrypto/2025-2 db/conf/pqcrypto/pqcrypto2025-2.html#YoshizumiOOKN25 streams/conf/pqcrypto Ryo Ohashi Hiroshi Onuki An Efficient Collision Attack on Castryck-Decru-Smith's Hash Function. 89-118 2025 PQCrypto (2) https://doi.org/10.1007/978-3-031-86602-9_4 conf/pqcrypto/2025-2 db/conf/pqcrypto/pqcrypto2025-2.html#OhashiO25 streams/conf/pqcrypto

Kohei Nakagawa Hiroshi Onuki SQIsign2DPush: Faster Signature Scheme Using 2-Dimensional Isogenies. 897 2025 2025 IACR Cryptol. ePrint Arch. https://eprint.iacr.org/2025/897 db/journals/iacr/iacr2025.html#NakagawaO25 streams/journals/iacr

Kohei Nakagawa Hiroshi Onuki Attacks on PRISM-id via Torsion over Small Extension Fields. 1602 2025 2025 IACR Cryptol. ePrint Arch. https://eprint.iacr.org/2025/1602 db/journals/iacr/iacr2025.html#NakagawaO25a streams/journals/iacr

Ryo Ohashi Hiroshi Onuki A collision attack on the LTZ hash function based on a conjecture on supersingular non-superspecial isogeny graphs of dimension 2. 1776 2025 2025 IACR Cryptol. ePrint Arch. https://eprint.iacr.org/2025/1776 db/journals/iacr/iacr2025.html#OhashiO25 streams/journals/iacr

Hiroshi Onuki Primality proving using elliptic curves with complex multiplication by imaginary quadratic fields of class number three. 102490 2024 99 Finite Fields Their Appl. https://doi.org/10.1016/j.ffa.2024.102490 db/journals/ffa/ffa99.html#Onuki24 streams/journals/ffa

Kaito Sato Hiroshi Onuki Tsuyoshi Takagi Explicit addition formulae on hyperelliptic curves of genus 2 for isogeny-based cryptography. 65-68 2024 16 JSIAM Lett. https://doi.org/10.14495/jsiaml.16.65 db/journals/jsiaml/jsiaml16.html#SatoOT24 streams/journals/jsiaml

Hiroshi Onuki Kohei Nakagawa Ideal-to-Isogeny Algorithm Using 2-Dimensional Isogenies and Its Application to SQIsign. 243-271 2024 ASIACRYPT (3) https://doi.org/10.1007/978-981-96-0891-1_8 conf/asiacrypt/2024-3 db/conf/asiacrypt/asiacrypt2024-3.html#OnukiN24 streams/conf/asiacrypt Kohei Nakagawa Hiroshi Onuki Wouter Castryck Mingjie Chen Riccardo Invernizzi Gioella Lorenzon Frederik Vercauteren SQIsign2D-East: A New Signature Scheme Using 2-Dimensional Isogenies. 272-303 2024 ASIACRYPT (3) https://doi.org/10.1007/978-981-96-0891-1_9 conf/asiacrypt/2024-3 db/conf/asiacrypt/asiacrypt2024-3.html#NakagawaOCCILV24 streams/conf/asiacrypt Kohei Nakagawa Hiroshi Onuki QFESTA: Efficient Algorithms and Parameters for FESTA Using Quaternion Algebras. 75-106 2024 CRYPTO (5) https://doi.org/10.1007/978-3-031-68388-6_4 conf/crypto/2024-5 db/conf/crypto/crypto2024-5.html#NakagawaO24 streams/conf/crypto Tomoki Moriya Hiroshi Onuki Maozhi Xu Guoqing Zhou Adaptive Attacks Against FESTA Without Input Validation or Constant-Time Implementation. 3-19 2024 PQCrypto (2) https://doi.org/10.1007/978-3-031-62746-0_1 conf/pqcrypto/2024-2 db/conf/pqcrypto/pqcrypto2024-2.html#MoriyaOXZ23

Kohei Nakagawa Hiroshi Onuki SQIsign2D-East: A New Signature Scheme Using 2-dimensional Isogenies. 771 2024 2024 IACR Cryptol. ePrint Arch. https://eprint.iacr.org/2024/771 db/journals/iacr/iacr2024.html#NakagawaO24

Hiroshi Onuki Kohei Nakagawa Ideal-to-isogeny algorithm using 2-dimensional isogenies and its application to SQIsign. 778 2024 2024 IACR Cryptol. ePrint Arch. https://eprint.iacr.org/2024/778 db/journals/iacr/iacr2024.html#OnukiN24

Ryo Yoshizumi Hiroshi Onuki Ryo Ohashi Momonari Kudo Koji Nuida Efficient theta-based algorithms for computing (ℓ, ℓ)-isogenies on Kummer surfaces for arbitrary odd ℓ. 1519 2024 2024 IACR Cryptol. ePrint Arch. https://eprint.iacr.org/2024/1519 db/journals/iacr/iacr2024.html#YoshizumiOOKN24 streams/journals/iacr

Ryo Ohashi Hiroshi Onuki An efficient collision attack on Castryck-Decru-Smith's hash function. 1776 2024 2024 IACR Cryptol. ePrint Arch. https://eprint.iacr.org/2024/1776 db/journals/iacr/iacr2024.html#OhashiO24 streams/journals/iacr

Kohei Nakagawa Hiroshi Onuki Atsushi Takayasu Tsuyoshi Takagi L1-norm ball for CSIDH: Optimal strategy for choosing the secret key space. 70-88 2023 March 328 Discret. Appl. Math. https://doi.org/10.1016/j.dam.2022.12.002 db/journals/dam/dam328.html#NakagawaOTT23

Tomoki Moriya Hiroshi Onuki Tsuyoshi Takagi How to construct CSIDH on Edwards curves. 102310 2023 December 92 Finite Fields Their Appl. https://doi.org/10.1016/j.ffa.2023.102310 db/journals/ffa/ffa92.html#MoriyaOT23

Saki Otsuki Hiroshi Onuki Tsuyoshi Takagi Improvement of the square-root Vélu's formulas for isogeny-based cryptography. 61-64 2023 15 JSIAM Lett. https://doi.org/10.14495/jsiaml.15.61 db/journals/jsiaml/jsiaml15.html#OtsukiOT23

Kohei Nakagawa Hiroshi Onuki QFESTA: Efficient Algorithms and Parameters for FESTA using Quaternion Algebras. 1468 2023 2023 IACR Cryptol. ePrint Arch. https://eprint.iacr.org/2023/1468 db/journals/iacr/iacr2023.html#NakagawaO23

Tomoki Moriya Hiroshi Onuki Yusuke Aikawa Tsuyoshi Takagi Lower bound of costs of formulas to compute image curves of 3-isogenies in the framework of generalized Montgomery coordinates. 1511 2023 2023 IACR Cryptol. ePrint Arch. https://eprint.iacr.org/2023/1511 db/journals/iacr/iacr2023.html#MoriyaOAT23

Shu Takahashi Hiroshi Onuki Tsuyoshi Takagi Explicit construction of the square-root Vélu's formula on Edwards curves. 108-110 2022 14 JSIAM Lett. https://doi.org/10.14495/jsiaml.14.108 db/journals/jsiaml/jsiaml14.html#TakahashiOT22

Hiroshi Onuki Tomoki Moriya Radical Isogenies on Montgomery Curves. 473-497 2022 Public Key Cryptography (1) https://doi.org/10.1007/978-3-030-97121-2_17 conf/pkc/2022-1 db/conf/pkc/pkc2022-1.html#OnukiM22

Tomoki Moriya Hiroshi Onuki Yusuke Aikawa Tsuyoshi Takagi The Generalized Montgomery Coordinate: A New Computational Tool for Isogeny-based Cryptography. 150 2022 2022 IACR Cryptol. ePrint Arch. https://eprint.iacr.org/2022/150 db/journals/iacr/iacr2022.html#MoriyaOAT22

Hiroshi Onuki On the key generation in SQISign. 900 2022 2022 IACR Cryptol. ePrint Arch. https://eprint.iacr.org/2022/900 db/journals/iacr/iacr2022.html#Onuki22

Hiroshi Onuki On oriented supersingular elliptic curves. 101777 2021 69 Finite Fields Their Appl. https://doi.org/10.1016/j.ffa.2020.101777 db/journals/ffa/ffa69.html#Onuki21

Hiroshi Onuki Tomoki Moriya Radical Isogenies on Montgomery Curves. 699 2021 2021 IACR Cryptol. ePrint Arch. https://eprint.iacr.org/2021/699 db/journals/iacr/iacr2021.html#OnukiM21

Hiroshi Onuki Yusuke Aikawa Tsutomu Yamazaki Tsuyoshi Takagi A Constant-Time Algorithm of CSIDH Keeping Two Points. 1174-1182 2020 103-A IEICE Trans. Fundam. Electron. Commun. Comput. Sci. 10 https://doi.org/10.1587/transfun.2019DMP0008 http://search.ieice.org/bin/summary.php?id=e103-a_10_1174 db/journals/ieiceta/ieiceta103.html#OnukiAYT20

Tomoki Moriya Hiroshi Onuki Tsuyoshi Takagi SiGamal: A Supersingular Isogeny-Based PKE and Its Application to a PRF. 551-580 2020 ASIACRYPT (2) https://doi.org/10.1007/978-3-030-64834-3_19 conf/asiacrypt/2020-2 db/conf/asiacrypt/asiacrypt2020-2.html#MoriyaOT20 Tomoki Moriya Hiroshi Onuki Tsuyoshi Takagi How to Construct CSIDH on Edwards Curves. 512-537 2020 CT-RSA https://doi.org/10.1007/978-3-030-40186-3_22 conf/ctrsa/2020 db/conf/ctrsa/ctrsa2020.html#MoriyaOT20 Fabio Campos Matthias J. Kannwischer Michael Meyer 0001 Hiroshi Onuki Marc Stöttinger Trouble at the CSIDH: Protecting CSIDH with Dummy-Operations Against Fault Injection Attacks. 57-65 2020 FDTC https://doi.org/10.1109/FDTC51366.2020.00015 conf/fdtc/2020 db/conf/fdtc/fdtc2020.html#CamposKMOS20 Hiroshi Onuki Yusuke Aikawa Tsuyoshi Takagi The Existence of Cycles in the Supersingular Isogeny Graphs Used in SIKE. 358-362 2020 ISITA https://ieeexplore.ieee.org/document/9366119 conf/isita/2020 db/conf/isita/isita2020.html#OnukiAT20 Hiroshi Onuki Tsuyoshi Takagi On Collisions Related to an Ideal Class of Order 3 in CSIDH. 131-148 2020 IWSEC https://doi.org/10.1007/978-3-030-58208-1_8 conf/iwsec/2020 db/conf/iwsec/iwsec2020.html#OnukiT20

Kohei Nakagawa Hiroshi Onuki Atsushi Takayasu Tsuyoshi Takagi L<sub>1</sub>-Norm Ball for CSIDH: Optimal Strategy for Choosing the Secret Key Space. 181 2020 2020 IACR Cryptol. ePrint Arch. https://eprint.iacr.org/2020/181 db/journals/iacr/iacr2020.html#NakagawaOTT20

Hiroshi Onuki Yusuke Aikawa Tsuyoshi Takagi The Existence of Cycles in the Supersingular Isogeny Graphs Used in SIKE. 439 2020 2020 IACR Cryptol. ePrint Arch. https://eprint.iacr.org/2020/439 db/journals/iacr/iacr2020.html#OnukiAT20

Tomoki Moriya Hiroshi Onuki Tsuyoshi Takagi SiGamal: A supersingular isogeny-based PKE and its application to a PRF. 613 2020 2020 IACR Cryptol. ePrint Arch. https://eprint.iacr.org/2020/613 db/journals/iacr/iacr2020.html#MoriyaOT20

Fabio Campos Matthias J. Kannwischer Michael Meyer 0001 Hiroshi Onuki Marc Stöttinger Trouble at the CSIDH: Protecting CSIDH with Dummy-Operations against Fault Injection Attacks. 1005 2020 2020 IACR Cryptol. ePrint Arch. https://eprint.iacr.org/2020/1005 db/journals/iacr/iacr2020.html#CamposKMOS20

Hiroshi Onuki Yusuke Aikawa Tsutomu Yamazaki Tsuyoshi Takagi (Short Paper) A Faster Constant-Time Algorithm of CSIDH Keeping Two Points. 23-33 2019 IWSEC https://doi.org/10.1007/978-3-030-26834-3_2 conf/iwsec/2019 db/conf/iwsec/iwsec2019.html#OnukiAYT19

Hiroshi Onuki Yusuke Aikawa Tsutomu Yamazaki Tsuyoshi Takagi A Faster Constant-time Algorithm of CSIDH keeping Two Torsion Points. 353 2019 2019 IACR Cryptol. ePrint Arch. https://eprint.iacr.org/2019/353 db/journals/iacr/iacr2019.html#OnukiAYT19

Tomoki Moriya Hiroshi Onuki Tsuyoshi Takagi How to Construct CSIDH on Edwards Curves. 843 2019 2019 IACR Cryptol. ePrint Arch. https://eprint.iacr.org/2019/843 db/journals/iacr/iacr2019.html#MoriyaOT19

Hiroshi Onuki Tsuyoshi Takagi On collisions related to an ideal class of order 3 in CSIDH. 1209 2019 2019 IACR Cryptol. ePrint Arch. https://eprint.iacr.org/2019/1209 db/journals/iacr/iacr2019.html#OnukiT19

Hiroshi Onuki Tadanori Teruya Naoki Kanayama Shigenori Uchiyama The optimal ate pairing over the Barreto-Naehrig curve via parallelizing elliptic nets. 9-12 2016 8 JSIAM Lett. https://doi.org/10.14495/jsiaml.8.9 db/journals/jsiaml/jsiaml8.html#OnukiTKU16

Hiroshi Onuki Tadanori Teruya Naoki Kanayama Shigenori Uchiyama Faster Explicit Formulae for Computing Pairings via Elliptic Nets and Their Parallel Computation. 319-334 2016 IWSEC https://doi.org/10.1007/978-3-319-44524-3_19 conf/iwsec/2016 db/conf/iwsec/iwsec2016.html#OnukiTKU16 Yusuke Aikawa Fabio Campos Wouter Castryck Mingjie Chen Shota Inoue Riccardo Invernizzi Naoki Kanayama Matthias J. Kannwischer Momonari Kudo Gioella Lorenzon Michael Meyer 0001 Tomoki Moriya Kohei Nakagawa Koji Nuida Ryo Ohashi Saki Otsuki Kaito Sato Masaomi Shibata Marc Stöttinger Tsuyoshi Takagi Shu Takahashi Atsushi Takayasu Tadanori Teruya Shigenori Uchiyama Frederik Vercauteren Maozhi Xu Tsutomu Yamazaki Ryo Yoshizumi Guoqing Zhou