中井 雄士 Takeshi Nakai

2011/4  –  2015/3

　電気通信大学 情報理工学部総合情報学科

2015/4  –  2017/3 

　電気通信大学大学院 情報理工学研究科総合情報学専攻 博士課程前期 (太田・岩本研究室): 修士(工学) 取得

2017/4  –  2020/3 

　SCSK株式会社

2020/4  –  2021/3 

　電気通信大学大学院 情報理工学研究科情報学専攻 博士課程後期 (岩本・渡邉研究室): 博士(工学) 取得

　　　学位論文: (英) Private Permutations in Card-Based Cryptography

　　　　　　　  (和) 秘匿置換を用いたカードベース暗号に関する研究

　日本学術振興会特別研究員 DC1 (電気通信大学 岩本・渡邉研究室)

2021/4  –  2022/3 

　日本学術振興会特別研究員 PD  (電気通信大学 岩本・渡邉研究室)  ※学位取得に伴う資格変更 

2022/4  –  現在 

　豊橋技術科学大学 情報・知能工学系 助教 [研究室HP] 

査読付き学術論文誌

1. Secure Multi-party Computation with Legally-Enforceable Fairness
   T. Nakai and K. Shinagawa, International Journal of Information Security, vol. 23, Springer, 2024.

2. Card-based Protocols for Private Set Intersection and Union

A. Doi, T. Ono, Y. Abe, T. Nakai, K. Shinagawa, Y. Watanabe, K. Nuida, and M. Iwamoto, New Generation Computing, vol. 42, Springer, 2024.

3. Card-based Cryptography with a Standard Deck of Cards, Revisited: Efficient Protocols in the Private Model

T. Nakai, K. Iwanari, T. Ono, Y. Abe, Y. Watanabe, and M. Iwamoto, New Generation Computing, vol. 42, Springer, 2024.

4. Perfectly-Sound Physical Zero-Knowledge Proofs for Instant Insanity

K. Hatsugai, Y. Abe, T. Nakai, K. Shinagawa, Y. Watanabe, and M. Iwamoto, IEICE transactions on fundamentals, vol. J107-A No.3,  IEICE, 2024  (in Japanese). 

5. Constant-Round Linear-Broadcast Secure Computation with Penalties
   T. Nakai and K. Shinagawa, Theoretical Computer Science, vol. 959, Elsevier, 2023. [arXiv ver.]

6. A Computationally Efficient Card-Based Majority Voting Protocol with Fewer Cards in the Private Model
   Y. Abe, T. Nakai, Y. Watanabe, M. Iwamoto, and K. Ohta, IEICE Transactions on Fundamentals, vol. E106.A, IEICE, 2023. 

7. How to Make a Secure Index for Searchable Symmetric Encryption, Revisited
   Y. Watanabe, T. Nakai, K. Ohara, T. Nojima, Y. Liu, M. Iwamoto, and K. Ohta, IEICE Transactions on Fundamentals, vol. E105.A, IEICE, 2022. [eprint ver.]

8. Efficient Card-based Majority Voting Protocols
   Y. Abe, T. Nakai, Y. Kuroki, S. Suzuki, Y. Koga, Y. Watanabe, M. Iwamoto, and K. Ohta, New Generation Computing, vol. 40, Springer, 2022.

9. Secure Computation for Threshold Functions with Physical Cards: Power of Private Permutations
   T. Nakai, S. Shirouchi, Y. Tokushige, M. Iwamoto, and K. Ohta,  New Generation Computing, vol. 40, Springer, 2022.

10. How to Solve Millionaires’ Problem with Two Kinds of Cards
    T. Nakai, Y. Misawa, Y. Tokushige, M. Iwamoto, and K. Ohta, New Generation Computing, vol. 39, Springer, 2021.

査読付き国際会議

1. Secure Computation with Penalties, Revisited: How to Handle Coins with Various Colors
   T. Nakai, The Cryptographers' Track at RSA Conference (CT-RSA 2025), LNCS 15598, Springer, 2025.

2. Card-based Secure Sorting Protocols based on the Sorting Networks
   K. Kato, T. Nakai, and K. Suzuki, 11th International Conference on Advanced Informatics: Concepts, Theory and Applications (ICAICTA 2024), IEEE, 2024.

3. Search Result Verifiability in Multi-User Dynamic Searchable Symmetric Encryption
   M. Son, T. Nakai, and K. Suzuki, 11th International Conference on Advanced Informatics: Concepts, Theory and Applications (ICAICTA 2024), IEEE, 2024.

4. Constant-Deposit Multiparty Lotteries on Bitcoin for Arbitrary Number of Players and Winners
   S. Uchizono, T. Nakai, Y. Watanabe, and M. Iwamoto, 26th Annual International Conference on Information Security and Cryptography (ICISC 2023), LNCS 14562, Springer, 2024.

5. Single-Shuffle Card-Based Protocols with Six Cards per Gate
   T. Ono, K. Shinagawa, T. Nakai, Y. Watanabe, and M. Iwamoto, 26th Annual International Conference on Information Security and Cryptography (ICISC 2023), LNCS 14562, Springer, 2024.

6. The Two Sheriffs Problem: Cryptographic Formalization and Generalization
   K. Sugimoto, T. Nakai, Y. Watanabe, and M. Iwamoto, 16th Annual International Conference on Combinatorial Optimization and Applications (COCOA 2023), LNCS 14461, Springer, 2023.

7. Secure Multi-Party Computation with Legally-Enforceable Fairness

T. Nakai and K. Shinagawa, 25th International Conference on Information and Communications Security (ICICS 2023), LNCS 14252, Springer, 2023. 

8. An Improvement of Multi-Party Private Set Intersection Based on Oblivious Programmable PRFs
   S. Shimizu, T. Nakai, Y. Watanabe, and M. Iwamoto, 2022 International Symposium on Information Theory and its Applications (ISITA 2022), IEEE, 2022. 

9. Card-based Cryptographic Protocols for Private Set Intersection
   A. Doi, T. Ono, T. Nakai, K. Shinagawa, Y. Watanabe, K. Nuida, and M. Iwamoto, 2022 International Symposium on Information Theory and its Applications (ISITA 2022), IEEE, 2022. 

10. Secure Computation with Non-equivalent Penalties in Constant Rounds
    T. Nakai and K. Shinagawa, 3rd International Conference on Blockchain Economics, Security and Protocols (Tokenomics 2021), Open Access Series in Informatics (OASIcs), vol. 97, Schloss Dagstuhl, 2022. 

11. Four Cards Are Enough for Card-Based Three-Input Voting Protocol Utilizing Private Permutations
    T. Nakai, S. Shirouchi, Y. Tokushige, M. Iwamoto, and K. Ohta, 10th International Conference on Information Theoretic Security (ICITS 2017), LNCS 10681, Springer, 2017.

12. Efficient Card-Based Cryptographic Protocols for Millionaires’ Problem Utilizing Private Permutations
    T. Nakai, Y. Misawa, Y. Tokushige, M. Iwamoto, and K. Ohta, 15th International Conference on Cryptology and Network Security (CANS 2016), LNCS 10052, Springer, 2016.