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I am a researcher of cryptography at NTT, Japan. I am mainly working on advanced cryptosystems based on pairings and multi-party computation.
Note: I have been temporarily transferred to NTT Research from September 2024 (My current affiliation is NTT Research).
Degrees
Degrees
Ph.D. Informatics, Kyoto University, 2021 (Thesis: Towards Practical Inner Product Functional Encryption)
M.S. Informatics, Kyoto University, 2017 (Supervisors: Tatsuaki Okamoto, Masayuki Abe)
B.S. Veterinary Medicine, Hokkaido University, 2012
Publications
Publications
Conference Papers
2024
A Modular Approach to Registered ABE for Unbounded Predicates
Nuttapong Attrapadung, Junichi Tomida. CRYPTO 2024
2023
Secure Statistical Analysis on Multiple Datasets: Join and Group-By
Gilad Asharov, Koki Hamada, Ryo Kikuchi, Ariel Nof, Benny Pinkas, Junichi Tomida. ACM CCS 2023
Communication-Efficient Inner Product Private Join and Compute with Cardinality
Koji Chida, Koki Hamada, Atsunori Ichikawa, Masanobu Kii, Junichi Tomida. AsiaCCS 2023
Attribute-Based Multi-input FE (and More) for Attribute-Weighted Sums
Shweta Agrawal, Junichi Tomida, Anshu Yadav. CRYPTO 2023
Unbounded Quadratic Functional Encryption and More from Pairings
Junichi Tomida. EUROCRYPT 2023
Making the Identity-Based Diffie-Hellman Key Exchange Efficiently Revocable
Kohei Nakagawa, Atsushi Fujioka, Akira Nagai, Junichi Tomida, Keita Xagawa, Kan Yasuda. LATINCRYPT 2023
2022
Efficient Secure Three-Party Sorting with Applications to Data Analysis and Heavy Hitters
Gilad Asharov, Koki Hamada, Dai Ikarashi, Ryo Kikuchi, Ariel Nof, Benny Pinkas, Katsumi Takahashi, Junichi Tomida. ACM CCS 2022
Multi-Input Quadratic Functional Encryption: Stronger Security, Broader Functionality
Shweta Agrawal, Rishab Goyal, Junichi Tomida. TCC 2022
2021
Revocable Hierarchical Identity-Based Authenticated Key Exchange
Yuki Okano, Junichi Tomida, Akira Nagai, Kazuki Yoneyama, Atsushi Fujioka, Koutarou Suzuki. ICISC 2021
Multi-Party Functional Encryption
Shweta Agrawal, Rishab Goyal, Junichi Tomida. TCC 2021.
Multi-Input Quadratic Functional Encryption from Pairings
Shweta Agrawal, Rishab Goyal, Junichi Tomida. CRYPTO 2021.
2020
Unbounded Dynamic Predicate Compositions in ABE from Standard Assumptions
Nuttapong Attrapadung, Junichi Tomida. ASIACRYPT 2020.
Fast, Compact, and Expressive Attribute-Based Encryption.
Junichi Tomida, Yuto Kawahara, Ryo Nishimaki. PKC 2020.
2019
Tightly Secure Inner Product Functional Encryption: Multi-Input and Function-Hiding Constructions
Junichi Tomida. ASIACRYPT 2019.
Strongly Secure Identity-Baed Key Exchange with Single Pairing Operation
Junichi Tomida, Atsushi Fujioka, Akira Nagai, Koutarou Suzuki. ESORICS 2019.
2018
Unbounded Inner Product Functional Encryption from Bilinear Maps
Junichi Tomida, Katsuyuki Takashima. ASIACRYPT 2018.
Full-Hiding (Unbounded) Multi-input Inner Product Functional Encryption from the k-Linear Assumption
Pratish Datta, Tatsuaki Okamoto, Junichi Tomida. PKC 2018.
2016
Efficient Functional Encryption for Inner-Product Values with Full-Hiding Security
Junichi Tomida, Masayuki Abe, Tatsuaki Okamoto. ISC 2016.
Journal Articles
2021
Fast, Compact, and Expressive Attribute-Based Encryption
Junichi Tomida, Atsushi Fujioka, Akira Nagai, Koutarou Suzuki. Designs, Codes and Cryptography 2021.
Strongly Secure Identity-Baed Key Exchange with Single Pairing Operation
Junichi Tomida, Atsushi Fujioka, Akira Nagai, Koutarou Suzuki. IEICE Trans. Fundam. Electron. Commun. Comput. Sci. 2021.
2020
Efficient Inner Product Functional Encryption with Full-Hiding Security
Junichi Tomida, Masayuki Abe, Tatsuaki Okamoto. IEICE Trans. Fundam. Electron. Commun. Comput. Sci. 2020.
Unbounded Inner Product Functional Encryption from Bilinear Maps
Junichi Tomida, Katsuyuki Takashima. Japan Journal of Industrial and Applied Mathematics 2020.
Tightly secure inner product functional encryption: Multi-input and function-hiding constructions
Junichi Tomida, Theoretical Computer Science 2020.
Program Committee
Program Committee
ASIACRYPT2024, SCN 2024, EUROCRYPT 2024
Invited Talks
Invited Talks
Unbounded Inner Product Functional Encryption from Bilinear Maps
WCIS 2019
Domestic Workshops in Japan
Domestic Workshops in Japan
データベースの等結合後に加重合計を求める秘密計算プロトコル
Junichi Tomida, Masanobu Kii, Koki Hamada, Atsunori Ichikawa, Koji Chida. SCIS2022
緊密安全な内積関数型暗号
Junichi Tomida. SCIS 2019.
（アリティに制限を持たない）関数秘匿複数入力内積関数型暗号
Pratish Datta, Tatsuaki Okamoto, Junichi Tomida. SCIS 2018.
より弱い仮定に基づく効率的な完全秘匿性を持つ内積値暗号
Junichi Tomida, Masayuki Abe, Tatsuaki Okamoto. SCIS 2017.
Adaptively Secure Functional Encryption for Inner-Product Values
Junichi Tomida, Masayuki Abe, Tatsuaki Okamoto. SCIS 2016.
Awards
Awards
Telecom System Technology Award 2023
SCIS 2018 Paper Award
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