研究業績

業績は年代が新しいものから順に並んでいます。

2027

  1. IEICE:FHHY27
    Multi-Designated Verifier Ring Signature: Generic Construction from Standard Primitives
    Yuuki Fujita, Keisuke Hara, Keitaro Hashimoto, and Kyosuke Yamashita
    IEICE TRANSACTIONS on Fundamentals, Mar 2027
    IEICE

2026

  1. CiC:HOS26
    Signatures with Tight Adaptive Corruptions from Search Assumptions
    Keitaro Hashimoto, Wakaha Ogata, and Yusuke Sakai
    IACR Communications in Cryptology, Oct 2026
    IACR EPRINT
  2. Crypto:GTH26
    Asymmetric Message Franking in the Plain Model: Generic and Efficient Constructions
    Milan Gonzalez-Thauvin, and Keitaro Hashimoto
    In Annual International Cryptology Conference (Crypto), Aug 2026
    acceptance rate = 189/781 (24.2%)
    Springer EPRINT Slides
  3. ACNS:HHMNT26
    (Re-)Formalization and Construction of Reusable and Robust Threshold Fuzzy Extractors
    Keisuke Hara, Keitaro Hashimoto, Takahiro Matsuda, Wataru Nakamura, and Kenta Takahashi
    In Applied Cryptography and Network Security (ACNS) Conference, Jun 2026
    acceptance rate = 59/282 (20.9%)
    Springer
  4. PrivCrypt:GTH26
    Efficient Asymmetric Message Franking in the Plain Model
    Milan Gonzalez-Thauvin, and Keitaro Hashimoto
    In International Workshop on Foundations and Applications of Privacy-Enhancing Cryptography (PrivCrypt), May 2026
    acceptance rate = 7/21 (33.3%). Full version is [Crypto:GTH26].
    PrivCrypt Web Site Slides
  5. SP:HKNW26
    Revisiting PQ WireGuard: A Comprehensive Security Analysis With a New Design Using Reinforced KEMs
    Keitaro Hashimoto, Shuichi Katsumata, Guilhem Niot, and Thom Wiggers
    In IEEE Symposium on Security and Privacy (S&P), May 2026
    acceptance rate = 253/1995 (12.7%)
    IEEE EPRINT
  6. SCIS:HHMNT26
    ロバストかつ再利用可能なしきい値ファジー抽出器
    原啓祐,  橋本啓太郎,  松田隆宏,  中村渉, and  高橋健太
    2026年暗号と情報セキュリティシンポジウム (SCIS2026) , Jan 2026
    Full version is [ACNS:HHMNT26].
  7. SCIS:THHKMN26
    Fuzzy Data-to-Random プロトコル
    高橋健太,  原啓祐,  橋本啓太郎,  勝又秀一,  松田隆宏, and  中村渉
    2026年暗号と情報セキュリティシンポジウム (SCIS2026) , Jan 2026

2025

  1. IWSEC:FHHY25
    Multi-Designated Verifier Ring Signature: Generic Construction from Standard Primitives
    Yuuki Fujita, Keisuke Hara, Keitaro Hashimoto, and Kyosuke Yamashita
    In International Workshop on Security (IWSEC), Nov 2025
    acceptance rate = 27/95 (28.4%). Full version is [IEICE:FHHY27].
    Springer
  2. USENIX:HKP25
    Exploring How to Authenticate Application Messages in MLS: More Efficient, Post-Quantum, and Anonymous Blocklistable
    Keitaro Hashimoto, Shuichi Katsumata, and Guillermo Pascual-Perez
    In USENIX Security 2025, Aug 2025
    acceptance rate = 407/2385 (17.1%)
    USENIX EPRINT
  3. USENIX:HKW25
    Bundled Authenticated Key Exchange: A Concrete Treatment of (Post-Quantum) Signal’s Handshake Protocol
    Keitaro Hashimoto, Shuichi Katsumata, and Thom Wiggers
    In USENIX Security 2025, Aug 2025
    acceptance rate = 407/2385 (17.1%)
    Awarded USENIX EPRINT
  4. CiC:MKOH25
    Round-Optimal Authenticated Key Exchange with Full Forward Privacy
    Koki Matsui, Shoma Kanzaki, Wakaha Ogata, and Keitaro Hashimoto
    IACR Communications in Cryptology, Jul 2025
    IACR
  5. CSF:HYH25
    Foundations of Multi-Designated Verifier Signature: Comprehensive Formalization and New Constructions in Subset Simulation
    Keitaro Hashimoto, Kyosuke Yamashita, and Keisuke Hara
    In IEEE Computer Security Foundations Symposium (CSF), Jun 2025
    acceptance rate = 38/198 (19.2%)
    IEEE EPRINT Slides
  6. PKC:AAHHW25
    Key Revocation in Registered Attribute-Based Encryption
    Kyoichi Asano, Nuttapong Attrapadung, Keisuke Hara, Keitaro Hashimoto, and Yohei Watanabe
    In International Conference on Practice and Theory of Public-Key Cryptography (PKC), May 2025
    acceptance rate = 60/199 (30.2%)
    Springer Slides
  7. EPRINT:HOS25
    Signatures with Tight Adaptive Corruptions from Search Assumptions
    Keitaro Hashimoto, Wakaha Ogata, and Yusuke Sakai
    IACR Cryptology ePrint Archive , Jan 2025
    EPRINT
  8. SCIS:HIIOSSY25
    組み込み機器に対するソフトウェア印加の要求仕様策定に向けた脅威分析と課題提起
    橋本啓太郎,  井手口恒太,  伊東真理,  小川知之,  佐藤眞司,  辛星漢, and  吉田博隆
    2025年暗号と情報セキュリティシンポジウム (SCIS2025) , Jan 2025
  9. SCIS:FHHY25
    複数検証者指定リング署名の一般的構成
    藤田祐輝,  原啓祐,  橋本啓太郎, and  山下恭佑
    2025年暗号と情報セキュリティシンポジウム (SCIS2025) , Jan 2025
    Full version is [IWSEC:FHHY25].
  10. SCIS:MHO25
    Full Forward Privacy を持ち冗長な通信が不要な認証鍵交換
    松井航輝,  橋本啓太郎, and  尾形わかは
    2025年暗号と情報セキュリティシンポジウム (SCIS2025) , Jan 2025
    Full version is [CiC:MKOH25].
  11. SCIS:KHO25
    標準モデルで安全なプライバシー保護付き認証鍵交換のラウンド数削減
    神崎翔午,  橋本啓太郎, and  尾形わかは
    2025年暗号と情報セキュリティシンポジウム (SCIS2025) , Jan 2025
    Full version is [CiC:MKOH25].
  12. SCIS:AHH25
    IDベース暗号に対する受信者アナモルフィック暗号
    淺野京一,  橋本啓太郎, and  原啓祐
    2025年暗号と情報セキュリティシンポジウム (SCIS2025) , Jan 2025
  13. SCIS:HOS25
    A Tightly Secure Signature in the Multi-User Setting with Corruptions Based on Discrete-Logarithm Assumption
    Keitaro Hashimoto, Wakaha Ogata, and Yusuke Sakai
    2025年暗号と情報セキュリティシンポジウム (SCIS2025) , Jan 2025
    Full version is [CiC:HOS26].

2024

  1. CSS:AHHAW24
    A Generic Construction of Deletable Registered Attribute-Based Encryption from Slotted Registered Attribute-Based Encryption
    Kyoichi Asano, Keisuke Hara, Keitaro Hashimoto, Nuttapong Attrapadung, and Yohei Watanabe
    コンピュータセキュリティシンポジウム2024 (CSS 2024) , Oct 2024
    Full version is [PKC:AAHHW25].
    Awarded
  2. CSS:CHHTS24
    CCA安全な登録ベース暗号
    知久奏斗,  原啓祐,  橋本啓太郎,  冨田斗威, and  四方順司
    コンピュータセキュリティシンポジウム2024 (CSS 2024) , Oct 2024
    Full version is [CANS:CHHTS24].
    Awarded
  3. SCN:ZHO24
    Security Model for Authenticated Key Exchange, Reconsidered
    Xichen Zhang, Keitaro Hashimoto, and Wakaha Ogata
    In International Conference on Security and Cryptography for Networks (SCN), Sep 2024
    acceptance rate = 33/90 (36.7%)
    Springer
  4. CANS:CHHTS24
    How to Apply Fujisaki-Okamoto Transformation to Registration-Based Encryption
    Sohto Chiku, Keisuke Hara, Keitaro Hashimoto, Toi Tomita, and Junji Shikata
    In International Conference on Cryptology And Network Security (CANS), Sep 2024
    acceptance rate = 25/76 (32.9%)
    Springer
  5. CFAIL:YOH24
    Towards a Tightly Secure Signature in Multi-User Setting with Corruptions Based on Search Assumptions
    Hirofumi Yoshioka, Wakaha Ogata, and Keitaro Hashimoto
    In Conference for Failed Approaches and Insightful Losses in Cryptology (CFAIL), Aug 2024
    acceptance rate = 4/4 (100%)
    CFAIL Web Site EPRINT Video Slides
  6. RWC:HKPPW24
    More Efficient Protocols for Post-Quantum Secure Messaging
    Keitaro Hashimoto, Shuichi Katsumata, Eamonn W. Postlethwaite, Thomas Prest, and Bas Westerbaan
    In Real World Crypto Symposium (RWC), Mar 2024
    Talk based on [CCS:HKPPW21] and [AC:KKPP20].
    Video Slides
  7. DCC:THO24
    Chosen-Ciphertext Secure Code-Based Threshold Public Key Encryptions with Short Ciphertext
    Kota Takahashi, Keitaro Hashimoto, and Wakaha Ogata
    Designs, Codes and Cryptography, Feb 2024
    Springer
  8. SCIS:CHHS24
    BDH仮定に基づく高効率かつ強安全なIDベースマッチメイキング暗号
    知久奏斗,  橋本啓太郎,  原啓祐, and  四方順司
    2024年暗号と情報セキュリティシンポジウム (SCIS2024) , Jan 2024
    Full version is [EPRINT:CHHS23].
  9. SCIS:YOH24
    デジタル署名の複数ユーザセキュリティにおける帰着ロスの下限について
    吉岡啓史,  尾形わかは, and  橋本啓太郎
    2024年暗号と情報セキュリティシンポジウム (SCIS2024) , Jan 2024
    Full version is [CFAIL:YOH24].
  10. SCIS:HYH24
    On the Security of Multi-Designated Verifier Signature
    Keitaro Hashimoto, Kyosuke Yamashita, and Keisuke Hara
    2024年暗号と情報セキュリティシンポジウム (SCIS2024) , Jan 2024
    Full version is [CSF:HYH25].
  11. SCIS:HIOSSY24
    組み込み機器向けファームウェア更新における脅威抽出と課題提起
    橋本啓太郎,  伊東真理,  小川知之,  佐藤眞司,  辛星漢, and  吉田博隆
    2024年暗号と情報セキュリティシンポジウム (SCIS2024) , Jan 2024

2023

  1. EPRINT:CHHS23
    Identity-Based Matchmaking Encryption with Enhanced Privacy Against Chosen-Ciphertext Attacks
    Sohto Chiku, Keitaro Hashimoto, Keisuke Hara, and Junji Shikata
    IACR Cryptology ePrint Archive , Sep 2023
    EPRINT
  2. RWC:HKP23
    Metadata Protection for MLS and Its Variants
    Keitaro Hashimoto, Shuichi Katsumata, and Thomas Prest
    In Real World Crypto Symposium (RWC), Mar 2023
    acceptance rate = 37/135 (27.4%)
    Video Slides
  3. Ph.D. Thesis
    Construction and Analysis of Post-Quantum Key Exchange Protocols for Secure Messaging
    Keitaro Hashimoto
    Tokyo Institute of Technology , Mar 2023
    This is based on [J. Cryptol.:HKKP22], [CCS:HKPPW21] and [CCS:HKP22]. There are several typos.
    Awarded Tokyo Tech Research Repository

2022

  1. CCS:HKP22
    How to Hide MetaData in MLS-Like Secure Group Messaging: Simple, Modular, and Post-Quantum
    Keitaro Hashimoto, Shuichi Katsumata, and Thomas Prest
    In The ACM Conference on Computer and Communications Security (ACM CCS), Nov 2022
    acceptance rate = 218/971 (22.5%)
    Awarded ACM EPRINT Slides
  2. J. Cryptol.:HKKP22
    An Efficient and Generic Construction for Signal’s Handshake (X3DH): Post-Quantum, State Leakage Secure, and Deniable
    Keitaro Hashimoto, Shuichi Katsumata, Kris Kwiatkowski, and Thomas Prest
    Journal of Cryptology, May 2022
    Full version of [PKC:HKKP21].
    Springer EPRINT Code

2021

  1. CCS:HKPPW21
    A Concrete Treatment of Efficient Continuous Group Key Agreement via Multi-Recipient PKEs
    Keitaro Hashimoto, Shuichi Katsumata, Eamonn W. Postlethwaite, Thomas Prest, and Bas Westerbaan
    In The ACM Conference on Computer and Communications Security (ACM CCS), Nov 2021
    acceptance rate = 196/879 (22.2%)
    Awarded ACM EPRINT Video Code Slides
  2. PKC:HKKP21
    An Efficient and Generic Construction for Signal’s Handshake (X3DH): Post-Quantum, State Leakage Secure, and Deniable
    Keitaro Hashimoto, Shuichi Katsumata, Kris Kwiatkowski, and Thomas Prest
    In International Conference on Practice and Theory of Public-Key Cryptography (PKC), May 2021
    acceptance rate = 52/156 (33.3%)
    Awarded Springer EPRINT Video Code Slides
  3. SCIS:HKKP21
    Signal に適用可能な耐量子認証鍵交換プロトコルの設計と実装
    橋本啓太郎,  勝又秀一, Kris Kwiatkowski, and Thomas Prest
    2021年暗号と情報セキュリティシンポジウム (SCIS2021) , Jan 2021
    Full version is [PKC:HKKP21].
    Awarded

2020

  1. Master Thesis
    Certificateless signatureの構成法に関する研究
    Keitaro Hashimoto
    Tokyo Institute of Technology , Mar 2020
    A part of this work was published as [EPRINT:HOT19].
  2. SCIS:HOT20
    Certificateless signature の一般的構成法に対するタイトな帰着とDDH仮定に基づく構成
    橋本啓太郎,  尾形わかは, and  冨田斗威
    2020年暗号と情報セキュリティシンポジウム (SCIS2020) , Jan 2020
    Full version is [EPRINT:HOT19].

2019

  1. EPRINT:HOT19
    Tight reduction for generic construction of certificateless signature and its instantiation from DDH assumption
    Keitaro Hashimoto, Wakaha Ogata, and Toi Tomita
    IACR Cryptology ePrint Archive , Nov 2019
    EPRINT
  2. Inf. Sci.:HO19
    Unrestricted and compact certificateless aggregate signature scheme
    Keitaro Hashimoto, and Wakaha Ogata
    Information Sciences, Jun 2019
    Elsevier

2018

  1. Bachelor Thesis
    Certificateless Aggregate Signature Schemeの構成法と安全性に関する研究
    Keitaro Hashimoto
    Tokyo Institute of Technology , Mar 2018
    A part of this work was published as [Inf. Sci.:HO19].
  2. SCIS:HO18
    Certificateless Aggregate Signature Schemeの構成法と安全性に関する研究
    橋本啓太郎, and  尾形わかは
    2018年暗号と情報セキュリティシンポジウム (SCIS2018) , Jan 2018
    Full version is [Inf. Sci.:HO19].