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Okumura Shinya
奥村　伸也
Okumura Shinya
奥村　伸也
Graduate School of Engineering　Division of Electrical, Electronic and Information Engineering, Assistant Professor

Research History 4

  1. 2018/04/01 - Present
    Osaka University Graduate School of Engineering Division of Electrical, Electronic and Information Engineering　Assistant Professor

  2. 2017/02/01 - 2018/03/31
    Osaka University Graduate School of Engineering Division of Electrical, Electronic and Information Engineering　Assistant Professor

  3. 2016/05 - 2017/01
    公益財団法人九州先端科学技術研究所情報セキュリティ研究室・研究員

  4. 2015/04 - 2016/04
    九州大学マス・フォア・インダストリ研究所・学術研究員

Education 3

  1. Kyushu University　Graduate School of Mathematics

    2012/04 - 2015/03

  2. Kyusyu University

    2010/04 - 2012/03

  3. Kyushu University

    2008/04 - 2010/03

Professional Memberships 3

  1. 情報処理学会

  2. 日本応用数理学会

  3. 日本数学会

Research Areas 2

  1. Informatics / Information security /

  2. Natural sciences / Algebra /

Awards 4

  1. CSEC優秀研究賞

    城戸良祐, 森本和邦, 奥村伸也, 宮地充子　コンピュータセキュリティ研究会（CSEC）　2025/04

  2. 日本応用数理学会 2016年度若手優秀講演賞

    奥村 伸也　日本応用数理学会　2017/06

  3. 電子情報通信学会基礎・境界ソサイエティ 2016年度 情報セキュリティ研究奨励賞

    奥村 伸也　電子情報通信学会　2017/01

  4. CANDAR 2016, Outstanding Paper Award

    Shinya Okumura, Koichiro Akiyama, Tsuyoshi Takagi　2016/11

Papers 17

  1. An Attack on Ring-LWE Using a Dynamically Adjustable Block Size BKW Algorithm

    Kenjiro Hirose, Shinya Okumura, Atsuko Miyaji

    Proceedings of the 20th Asia Joint Conference on Information Security (AsiaJCIS 2025)　2025　Research paper (international conference proceedings)

  2. Consideration on Defining Field for Efficient Ring-LWE

    Rintaro Yamada, Shinya Okumura, Atsuko Miyaji

    2024 19th Asia Joint Conference on Information Security (AsiaJCIS)　p. 25-32　2024/08/13　Research paper (international conference proceedings)

    Publisher: IEEE

  3. Revisiting an Extension of Kannan’s Embedding for Ring-LWE

    Satoshi Uesugi, Shinya Okumura, Atsuko Miyaji

    Proceedings of the 7th International Conference on Mobile Internet Security (Mobisec 2023)　2023/12

  4. On the Weakness of Non-Dual Ring-LWE Mod Prime Ideal q by Trace Map

    Tomoka TAKAHASHI, Shinya OKUMURA, Atsuko MIYAJI

    IEICE Transactions on Information and Systems　Vol. E106.D　No. 9　p. 1423-1434　2023/09/01　Research paper (scientific journal)

    Publisher: Institute of Electronics, Information and Communications Engineers (IEICE)

  5. On the Weakness of Ring-LWE mod Prime ideal q by Trace Map

    Tomoka Takahashi, Shinya Okumura, Atsuko Miyaji

    Proceedings of the 29th Selected Areas in Cryptography (SAC 2022), to appear　2022　Research paper (international conference proceedings)

  6. Revisiting Lattice-Based Attacks Using Trace Map for Ring-LWE

    Shinya Okumura, Shusaku Uemura, Momonari Kudo

    Proceedings of 2022 International Symposium on Information Theory and Its Applications, ISITA 2022, to appear.　2022　Research paper (international conference proceedings)

  7. Cryptography core technology

    Chen Mou Cheng, Kenta Kodera, Atsuko Miyaji, Shinya Okumura

    Security Infrastructure Technology for Integrated Utilization of Big Data: Applied to the Living Safety and Medical Fields　p. 5-33　2020/01/01　Part of collection (book)

  8. An Improved Security Analysis on an Indeterminate Equation Public Key Cryptosystem by Evaluation Attacks

    Akifumi Muroi, Shinya Okumura, Atsuko Miyaji

    Lecture Notes in Computer Science　Vol. 11959　p. 421-436　2019/09　Research paper (international conference proceedings)

  9. An Experimental Analysis on Lattice Attacks against Ring-LWE over Decomposition Fields

    Shota Terada, Hideto Nakano, Shinya Okumura, Atsuko Miyaji

    2018 International Symposium on Information Theory and Its Applications (ISITA), IEEE　p. 306-310　2018/10　Research paper (international conference proceedings)

    Publisher: IEEE

  10. Cryptanalysis of a public key cryptosystem based on Diophantine equations via weighted LLL reduction

    Jintai Ding, Momonari Kudo, Shinya Okumura, Tsuyoshi Takagi, Chengdong Tao

    Japan Journal of Industrial and Applied Mathematics　2018/06　Research paper (scientific journal)

  11. Security analysis of cryptosystems using short generators over ideal lattices

    Shinya Okumura, Shingo Sugiyama, Masaya Yasuda, Tsuyoshi Takagi

    Japan Journal of Industrial and Applied Mathematics　2018/05　Research paper (scientific journal)

    Publisher: Springer Japan

  12. A Publickey Encryption Scheme Based on Non-linear Indeterminate Equations

    Koichiro Akiyama, Yasuhiro Goto, Shinya Okumura, Tsuyoshi Takagi, Koji Nuida, Goichiro Hanaoka

    Lecture Notes in Computer Science　Vol. 10719　p. 215-234　2017/12　Research paper (international conference proceedings)

    Publisher: Springer, Cham

  13. On Analysis of Recovering Short Generator Problems via Upper and Lower Bounds of Dirichlet L-functions: Part 2

    Shinya Okumura

    Mathematical Modelling for Next-Generation Cryptography　p. 279-295　2017/07/26　Part of collection (book)

    Publisher: Springer Singapore

  14. An Estimate of the Complexity of the Section Finding Problem on Algebraic Surfaces

    Shinya Okumura, Koichiro Akiyama, Tsuyoshi Takagi

    2016 FOURTH INTERNATIONAL SYMPOSIUM ON COMPUTING AND NETWORKING (CANDAR)　p. 28-36　2016　Research paper (international conference proceedings)

  15. Cryptanalysis of a Public Key Cryptosystem Based on Diophantine Equations via Weighted LLL Reduction (Short Paper)

    Jintai Ding, Momonari Kudo, Shinya Okumura, Tsuyoshi Takagi, Chengdong Tao

    Lecture Notes in Computer Science　Vol. 9836　p. 305-315　2016　Research paper (international conference proceedings)

    Publisher: Springer International Publishing

  16. A public key cryptosystem based on diophantine equations of degree increasing type

    Pacific journal of mathematics for industry : PJMI　Vol. 7　No. 4　p. 33-45　2015/06　Research paper (scientific journal)

    Publisher: Institute of Mathematics for Industry, Kyushu University ; c2014-

  17. On the number of Fp-valued points of elliptic curves

    Okumura Shinya

    JMI : journal of math-for-industry　Vol. 5　p. 111-128　2013/07　Research paper (scientific journal)

    Publisher: Faculty of Mathematics, Kyushu University

Misc. 2

  1. An Homomorphic Encryption based on some kind of Indeterminate Equations

    Vol. 116　No. 207　p. 27-34　2016/09/02

    Publisher: 電子情報通信学会

  2. On the Possibility of Recovering Short Generators over Ideal Lattices for Cyclotomic Fields

    Vol. 116　No. 35　p. 25-32　2016/05/19

    Publisher: 電子情報通信学会

Presentations 24

  1. Revisiting Lattice-Based Attacks Using Trace Map for Ring-LWE

    Shinya Okumura, Shusaku Uemura, Momonari Kudo

    2022 International Symposium on Information Theory and Its Applications, ISITA 2022　2022/10/18

  2. トレース写像を用いたRing-LWE問題に対する格子攻撃の再考

    奥村 伸也, 上村 周作, 工藤 桃成

    2022年暗号と情報セキュリティシンポジウム　2022/01/21

  3. On the Security of Homomorphic Encryption Schemes Based on Ring-LWE Problem over Decomposition Fields

    2018/02/07

  4. グレブナー基底計算に関する正則性の次数の2つの定義について

    奥村伸也, 櫻井 幸一

    2017年暗号と情報セキュリティシンポジウム　2017/01/27

  5. ある準同型暗号の安全性とプライバシー保護線形回帰モデルの問題点について

    奥村 伸也, 櫻井 幸一

    2017年暗号と情報セキュリティシンポジウム　2017/01/26

  6. Security Analysis of a homomorphic encryption scheme based on discrete logarithm problem

    Shinya Okumura

    The 9th Work Shop among Asian Information Security Labs　2017/01

  7. 代数曲面暗号の安全性を支える求セクション問題の計算量評価

    奥村 伸也, 秋山 浩一郎, 高木 剛

    日本数学会異分野・異業種研究交流会　2016/10

  8. 円分体に対するイデアル格子上の短い生成元の復元可能性について

    奥村 伸也, 安田 雅哉, 高木 剛

    日本応用数理学会 2016年度 年会　2016/09

  9. Our Plan for Using Post-Quantum Cryptosystems for Trusted Infrastructure

    Shinya Okumura, Kouichi Sakurai

    The 11th Asia Joint Conference on Information Security (AsiaJCIS 2016)　2016/08

  10. 有限体上の代数曲面に関する求セクション問題から乗じる連立方程式の半正則性について

    奥村 伸也, 秋山 浩一郎, 高木 剛

    情報セキュリティ研究会　2016/07/15

  11. On the Security of Cryptosystems Using Short Generators Over Ideal Lattices for Cyclotomic Fields

    Shinya Okumura, Shingo Sugiyama, Masaya Yasuda, Tsuyoshi Takagi

    2016 Symposium on Cryptography and Information Security　2016/01/19

  12. Security Analysis of Cryptography on Ideal Lattice

    Shinya Okumura, Shingo Sugiyama, Masaya Yasuda, Tsuyoshi Takagi

    The 3rd International Workshop on Cybersecurity　2016/01

  13. 円分体の log-unit 格子上の最近ベクトル問題について

    奥村 伸也, 杉山 真吾, 安田 雅哉, 高木 剛

    日本応用数理学会2015年度 年会　2015/09

  14. A public key cryptosystem based on diophantine equations of degree increasing type

    Shinya Okumura

    Kick-off Meeting of IMI Australia Branch in La Trobe-Mathematics Bridge over the Pacific for Competitive Edge in Industry　2015/03

  15. A public key cryptosystem based on diophantine equations of degree increasing type

    2015/03

  16. A public key cryptosystem based on diophantine equations of degree increasing type

    2015/02

  17. ディオファントス方程式を用いた公開鍵暗号について

    奥村 伸也

    日本数学会異分野・異業種研究交流会　2014/10

  18. 代数曲面の求セクション問題の計算困難性の評価について

    奥村 伸也

    共化進社会システム創成拠点フォーラム　2014/03

  19. On the number of Fp-valued points of elliptic curves

    Shinya Okumura

    Forum Math-for-Industry 2021　2012/12

  20. On the number of Fp-valued points of elliptic curves

    2012/09

  21. Q上CMを持つ楕円曲線を modulo p した曲線の Fp-有理点の個数の素数性について

    奥村 伸也

    日本応用数理学会 2012年度 年会　2012/08

  22. On the number of Fp-valued points of elliptic curves

    2012/07

  23. On the number of Fp-valued points of elliptic curves

    2012/07

  24. On the number of Fp-valued points of elliptic curves

    2012/03

Academic Activities 4

  1. The 39th Symposium on Cryptography and Information Security

    Atsuko Miyaji

    2022/01/18 - 2022/01/21

  2. 九大IMI共同利用研究集会「ネットワークストレージのディペンダビリティ, ユーザビリティとセキュリティに対する秘密分散法の応用とその数学モデリング」

    穴田 啓晃

    2016/09/05 - 2016/10/07

  3. The 22nd Workshop on Elliptic Curve Cryptography (ECC 2018)

    Akira Otsuka (General Chair)

    2018/11 -

  4. The 15th InternationaConference on Applied Cryptography and Network Security (ACNS2017)

    Hiroaki Kikuchi (General Chair)

    2017/07 -