Keitaro Hashimoto (𣘺本 啓太郎)

Researcher at AIST | Researching cryptography to realize a secure world!

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I am a researcher at Security Assurance Scheme Research Team in Cyber Physical Security Research Center, National Institute of Advanced Industrial Science and Technology (AIST). I received my Bachelor’s degree in Engineering, Master’s degree in Engineering and Ph.D. in Engineering from Tokyo Institute of Technology in 2018, 2020 and 2023, respectively. My adviser is Prof. Wakaha Ogata. Furthermore, I completed Progressive Graduate Minor in Cybersecurity in 2020. Before I become a resercher at AIST, I worked as a research assistant at AIST from June 2020 to March 2023, and as a research fellowship for young scientists from April 2022 to March 2023.

I am skilled at provable security in cryptography. My research interests are board range of cryptography and information security, especially real-world cryptraphic technologies such as secure messaging and how to propote social implementation of such technologies. Also, I love to systematically analyze security of cryptographic primitives/protocols.

I am a compassionate and cooperative professional. I received the Outstanding Student Award in 2020, Tsujii Shigeo Security Award in 2021, 2022 and 2023, and Seiichi Tejima Ph.D. dissertation award in 2024.

News

2025-03-16 I will talk about “Authentication in MLS and Its Variants” invited by PEARG in IETF 122.
2025-02-05 One paper has been accepted at PKC 2025.
2025-01-25 Two papers have been accepted at Usenix Security 2025.
2025-01-23 One paper has been accepted at IEEE CSF 2025.
2025-01-06 Six technical reports will be presented in a domestic conference 2025 Symposium on Cryptography and Information Security (SCIS 2025). Please see my publication list for detail.

Selected publications

  1. PKC:AHHAW25
    Key Revocation in Registered Attribute-Based Encryption
    In International Conference on Practice and Theory of Public-Key Cryptography (PKC), May 2025
  2. CSF:HYH25
    Foundations of Multi-Designated Verifier Signature: Comprehensive Formalization and New Constructions in Subset Simulation
    Keitaro HashimotoKyosuke Yamashita, and Keisuke Hara
    In IEEE Computer Security Foundations Symposium (CSF), June 2025
  3. USENIX:HKP25
    Exploring How to Authenticate Application Messages in MLS: More Efficient, Post-Quantum, and Anonymous Blocklistable
    Keitaro HashimotoShuichi Katsumata, and Guillermo Pascual-Perez
    In Usenix Security 2025, August 2025
  4. USENIX:HKW25
    Bundled Authenticated Key Exchange: A Concrete Treatment of (Post-Quantum) Signal’s Handshake Protocol
    Keitaro HashimotoShuichi Katsumata, and Thom Wiggers
    In Usenix Security 2025, August 2025
  5. J. Cryptol.:HKKP22
    An Efficient and Generic Construction for Signal’s Handshake (X3DH): Post-Quantum, State Leakage Secure, and Deniable
    Keitaro HashimotoShuichi KatsumataKris Kwiatkowski, and Thomas Prest
    Journal of Cryptology, May 2022
    Full version of [PKC:HKKP21].
  6. CCS:HKPPW21
    A Concrete Treatment of Efficient Continuous Group Key Agreement via Multi-Recipient PKEs
    In The ACM Conference on Computer and Communications Security (ACM CCS), November 2021