Taishi Nakai

Affiliation

Kyoto University, Graduate School of Informatics, Informatics Major, Social Informatics Course, Ph.D. Program (2nd year)

Contact

Email: distributed.nakai [at] gmail.com (replace [at] with @)

Research Interests

Blockchain, Distributed Systems

Publications & Activities

Journal Articles (Peer-reviewed)

• Taishi Nakai, Akira Sakurai, Shiori Hironaka, Kazuyuki Shudo. “A Formulation of the Trilemma in Proof of Work Blockchain”, IEEE Access, 2024.

Refereed Proceedings

• Taishi Nakai, Akira Sakurai, Kazuyuki Shudo. “The More Halving Advances, the More Rational Double Spending Attack is”, IEEE ICCE 2025, Jan. 2025.
• Shinnosuke Masuda, Tsuyoshi Hasegawa, Taishi Nakai, Akira Sakurai, Kazuyuki Shudo. “High-Bandwidth Node Selection in Compact Block Relay”, IEEE GeeenCom 2024, 2024.
• Taishi Nakai, Kazuyuki Shudo, “Impacts on Fork Rate of Changes of Block Size and Block Generation Time for Blockchain Scalability”, IEEE ICCE 2024, Jan. 2024.
• Taishi Nakai, Akira Sakurai, Shiori Hironaka, Kazuyuki Shudo. “Blockchain Trilemma Described by a Formula”, IEEE Blockchain 2023, Dec. 2023.
  • 35 accepted out of 110 submissions

Non-refereed Papers

See the Japanese list of non-refereed papers.

Talks (Non-refereed)

• Taishi Nakai, “The Blockchain Trilemma Described by a Formula”, to members of the Ethereum Foundation including Vitalik Buterin, Aug. 2023.
• Taishi Nakai, “Towards Mathematical Formulation of the Blockchain Trilemma”, BCK 2023, Jan. 2023.

Invited Talks (Non-refereed)

• Taishi Nakai, “Mathematical Formulation of the Blockchain Trilemma and Its Impact”, The University of Tokyo — Research Association for Distributed Ledger and Its Applications, Dec. 2024.
• Taishi Nakai, “Mathematical Description of the Blockchain Trilemma”, Namera Conference #3, Jan. 2024.

Posters (Non-refereed)

• Taishi Nakai, “High decentralization does not necessarily improve 51% attack resistance”, ICT Innovation 2025, Feb. 2025.
• Taishi Nakai, “The Blockchain Trilemma Described by a Formula”, ICT Innovation 2024, Feb. 2024.

Research-related Awards

• Kyoto University President’s Award, Taishi Nakai, for multiple research achievements in blockchain, Kyoto University, Mar. 2025.
• The 40th TAF Telecom System Technology Student Award, Taishi Nakai, for “A Formulation of the Trilemma in Proof of Work Blockchain”, Mar. 2025.
• ICT Innovation 2025 Excellent Research Award, Taishi Nakai, “High decentralization does not necessarily improve 51% attack resistance”, Feb. 2025.
  • 6 selected out of 33 presentations
• SCIS 2024 Paper Award, Taishi Nakai, “Mathematical Formulation of the Blockchain Trilemma”, Jan. 2025.
  • 8 selected out of 228 papers
• Best Session Presentation Award, Taishi Nakai, “The More Halving Advances, the More Rational Double Spending Attack is”, IEEE ICCE 2025, Jan. 2025.
  • 1 selected out of 5 in session
• IEICE ISEC Research Encouragement Award, Taishi Nakai, “High decentralization does not necessarily improve 51% attack resistance”, Nov. 2024.
  • 8 student presentations among 66
• IPSJ CSS 2024 Best Paper Award, Taishi Nakai, “High decentralization does not necessarily improve 51% attack resistance”, Oct. 2024.
  • 2 selected out of 269
• IEICE Internet Architecture Research Award (Excellent Research Award), Taishi Nakai, “Blockchain Trilemma Described by a Formula”, May 2024.
  • 4 selected out of 100 in FY2023
• ICT Innovation 2024 Excellent Research Award, Taishi Nakai, “The Blockchain Trilemma Described by a Formula”, Feb. 2024.
  • 8 selected out of 55
• Excellent Master’s Thesis Award, Taishi Nakai, “The Blockchain Trilemma Described by a Formula”, Dept. of Social Informatics, Kyoto University, Feb. 2024.

Grants

As a PI

• 2024/10 – 2027/03: JST ACT-X (total 6,000,000 JPY, 2.5 years / 40k USD for 2.5 years)
• 2024/04 – 2027/03: JST Boost Fellowship (900,000 JPY per year / 6k USD per year)