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Biography#

I am a security researcher focused on threat analysis, defensive design, and security protocols. (Explore notes). My work occasionally extends to software engineering and data analysis. Outside of research, I enjoy working on security challenges.

First-Author Publications#

  • "Integration of PSI-CA and Differential Privacy for APPI Compliance" Authors: Kabuto Okajima Diaz Zazueta, Koji Chida
    Venue: The 111th IPSJ SIG Computer Security (CSEC) Joint Research Meeting, Niigata, Japan

  • "Block Hijacking Attack: Impact Evaluation on Liquid Network and Design Insights for Blockchain-based Scaling Solutions" Authors: Kabuto Okajima, Shin’ichiro Matsuo, Koji Chida
    Proceedings: 2025 IEEE International Conference on Blockchain and Cryptocurrency (ICBC), Pisa, Italy

  • "A Study on Anonymization Through Participation in iPWS Cup 2023" Authors: Kabuto Okajima, Koji Chida
    Proceedings: International Workshop on Security, IWSEC 2024, Kyoto, Japan

Experience#

  • Research Assistant / M.S. Student, Georgetown University — Washington, DC, USA–present
  • Chief Technology Officer, Physical Control Center Inc. — Osaka, Japan
  • Researcher, Gunma University — Gunma, Japan
  • Researcher, Commonwealth Cyber Initiative — Virginia, USA
  • Earlier Software Engineering Roles across Several Companies — Japan

Highlights#

  • Earned OSCP/OSCP+
  • 3rd Place (Team), C2C CTF 2025 Finals
  • 2nd Place, iPWS Cup 2024
  • 1st Place (Team), iPWS Cup 2023