Takashi Yamakawa (original) (raw)
I am a research scientist at NTT, Japan. My main research area is cryptography.
- Senior Distinguished Researcher at NTT Social Informatics Laboratories and NTT Research Center for Theoretical Quantum Information
- Oct. 2021-present: Affiliate Associate Professor at Yukawa Institute for Theoretical Physics, Kyoto University
- Jan. 2020-Apr. 2021: Visiting Associate Research Scholar at Princeton University (hosted by Prof. Mark Zhandry)
- Apr. 2016-Mar. 2017 Collaborative Researcher at National Institute of Advanced Industrial Science and Technology (AIST)
- Apr. 2014-Mar. 2017: JSPS Research Fellowship for Young Scientists (DC1)
- Aug. 2014-Sep. 2014: Internship at NTT Secure Platform Laboratories (Mentor: Ryo Nishimaki)
- Aug. 2012-Mar. 2014: Technical Staff at National Institute of Advanced Industrial Science and Technology (AIST)
- Apr. 2014-Mar. 2017 Ph.D in Science, The University of Tokyo (Supervisor: Prof. Noboru Kunihiro)
- Apr. 2012-Mar. 2014 Master of Science, The University of Tokyo (Supervisor: Prof. Noboru Kunihiro)
- Apr. 2008-Mar. 2012 Bachelor of Science, The University of Tokyo (Major: Mathematics)
See also DBLP and Google Scholar
The order of authors is alphabetical, unless otherwise noted.
(Most works done in 2016 or earlier use non-alphabetical order, and the others use alphabetical order. )
- Separating Non-Interactive Classical Verification of Quantum Computation from Falsifiable Assumptions
Mohammed Barhoush, Tomoyuki Morimae, Ryo Nishimaki, Takashi Yamakawa
arXiv ePrint - Multi-Copy Security in Unclonable Cryptography
Alper Çakan, Vipul Goyal, Fuyuki Kitagawa, Ryo Nishimaki, Takashi Yamakawa
arXiv - A Unified Approach to Quantum Key Leasing with a Classical Lessor
Fuyuki Kitagawa, Jiahui Liu, Shota Yamada, Takashi Yamakawa
arXiv, ePrint - Quantum Cryptography and Hardness of Non-Collapsing Measurements
Tomoyuki Morimae, Yuki Shirakawa, Takashi Yamakawa
arXiv, ePrint - Proofs of Quantum Memory
Minki Hhan, Tomoyuki Morimae, Yasuaki Okinaka, Takashi Yamakawa
arXiv, ePrint - From Worst-Case Hardness of NP to Quantum Cryptography via Quantum Indistinguishability Obfuscation
Tomoyuki Morimae, Yuki Shirakawa, Takashi Yamakawa
arXiv, ePrint - Anonymous Public-Key Quantum Money and Quantum Voting
Alper Çakan, Vipul Goyal, Takashi Yamakawa
presented at QIP 2025 and QCRYPT 2025
arXiv, ePrint - CountCrypt: Quantum Cryptography between QCMA and PP
Eli Goldin, Tomoyuki Morimae, Saachi Mutreja, Takashi Yamakawa
arXiv, ePrint
International Conferences
- Copy-Protection from Unclonable Puncturable Obfuscation, Revisited
Prabhanjan Ananth, Amit Behera, Zikuan Huang, Fuyuki Kitagawa, Takashi Yamakawa
Eurocrypt 2026
ePrint (A preliminary version appeared as Copy Protecting Cryptographic Functionalities over Entropic Inputs ePrint) - On the Cryptographic Futility of Non-Collapsing Measurements
Alper Çakan, Dakshita Khurana, Tomoyuki Morimae, Yuki Shirakawa, Kabir Tomer, Takashi Yamakawa
Eurocrypt 2026
arXiv - Foundations of Single-Decryptor Encryption
Fuyuki Kitagawa, Takashi Yamakawa
TCC 2025
ePrint - Untelegraphable Encryption and its Applications
Jeffrey Champion, Fuyuki Kitagawa, Ryo Nishimaki, Takashi Yamakawa
TCC 2025
also presented at TQC 2025
arXiv - Round-Efficient Composable Two-Party Quantum Computation
Vipul Goyal, Xiao Liang, Omkant Pandey, Yuhao Tang, Takashi Yamakawa
Asiacrypt 2025
ePrint - Almost-Total Puzzles and Their Applications
Xiao Liang, Omkant Pandey, Yuhao Tang, Takashi Yamakawa
Asiacrypt 2025
ePrint - MicroCrypt Assumptions with Quantum Input Sampling and Pseudodeterminism: Constructions and Separations
Mohammed Barhoush, Ryo Nishimaki, Takashi Yamakawa
Asiacrypt 2025
arXiv, ePrint - Quantum Lifting for Invertible Permutations and Ideal Ciphers
Alexandru Cojocaru, Minki Hhan, Qipeng Liu, Takashi Yamakawa, Aaram Yun
CRYPTO 2025
arXiv, ePrint also presented at QCRYPT 2025 and QIP 2026 - The Round Complexity of Black-Box Post-Quantum Secure Computation
Rohit Chatterjee, Xiao Liang, Omkant Pandey, Takashi Yamakawa
CRYPTO 2025
arXiv, ePrint video - On Collision Resistance from Group Actions
Takashi Yamakawa, Mark Zhandry CFAIL 2025
paper - Non-Committing Identity based Encryption: Constructions and Applications
Rishab Goyal, Fuyuki Kitagawa, Venkata Koppula, Ryo Nishimaki, Mahesh Sreekumar Rajasree, Takashi Yamakawa
PKC 2025
video (by Mahesh Sreekumar Rajasree) - Cryptographic Characterization of Quantum Advantage
Tomoyuki Morimae, Yuki Shirakawa, Takashi Yamakawa
STOC 2025
also presented at QIP 2025
arXiv, ePrint - A New World in the Depths of Microcrypt: Separating OWSGs and Quantum Money from QEFID
Amit Behera, Giulio Malavolta, Tomoyuki Morimae, Tamer Mour, Takashi Yamakawa
Eurocrypt 2025 (soft merge with this paper)
also presented at TQC 2025
arXiv, ePrint video (by Amit Behera, merged with a talk by John Bostanci) - A Simple Framework for Secure Key Leasing
Fuyuki Kitagawa, Tomoyuki Morimae, Takashi Yamakawa
Eurocrypt 2025
arXiv, ePrint video (by Tomoyuki Morimae) - Robust Combiners and Universal Constructions for Quantum Cryptography
Taiga Hiroka, Fuyuki Kitagawa, Ryo Nishimaki, Takashi Yamakawa
TCC 2024
arXiv, ePrint - Quantum Unpredictability
Tomoyuki Morimae, Shogo Yamada, Takashi Yamakawa
Asiacrypt 2024
also presented at AQIS 2024 (short talk)
arXiv, ePrint video (by Shogo Yamada) - Exponential Quantum One-Wayness and EFI Pairs
Giulio Malavolta, Tomoyuki Morimae, Michael Walter, Takashi Yamakawa
SCN 2024
arXiv - Unconditionally Secure Commitments with Quantum Auxiliary Inputs
Tomoyuki Morimae, Barak Nehoran, Takashi Yamakawa
CRYPTO 2024 (soft merge with this paper)
also presented at QCRYPT 2024 and QIP 2025 (merged with this paper)
arXiv, ePrint video (by Barak Nehoran) - Quantum Public-Key Encryption with Tamper-Resilient Public Keys from One-Way Functions.
Fuyuki Kitagawa, Tomoyuki Morimae, Ryo Nishimaki, Takashi Yamakawa
CRYPTO 2024
also presented at QIP 2024
arXiv ePrint video - Quantum Complexity for Discrete Logarithms and Related Problems
Minki Hhan, Takashi Yamakawa, Aaram Yun
CRYPTO 2024
also presented at AQIS 2023 (long talk) and TQC 2024 (talk only (merged with this paper))
arXiv, ePrint video (by Minki Hhan) - Quantum Advantage from One-Way Functions
Tomoyuki Morimae, Takashi Yamakawa
CRYPTO 2024
also presented at QCRYPT 2023 and TQC 2024 (talk only)
arXiv ePrint video (by Tomoyuki Morimae) - Revocable Quantum Digital Signatures
Tomoyuki Morimae, Alexander Poremba, Takashi Yamakawa
TQC 2024 (talk + proceedings)
arXiv ePrint video - One-Wayness in Quantum Cryptography
Tomoyuki Morimae, Takashi Yamakawa
TQC 2024 (talk + proceedings)
arXiv, ePrint video (by Tomoyuki Morimae) - Certified Everlasting Secure Collusion-Resistant Functional Encryption, and More
Taiga Hiroka, Fuyuki Kitagawa Tomoyuki Morimae, Ryo Nishimaki, Tapas Pal, Takashi Yamakawa
Eurocrypt 2024
arXiv ePrint video (by Ryo Nishimaki)
(A preliminary version appeared as Certified Everlasting Functional Encryption. arXiv) - Classical vs Quantum Advice and Proofs under Classically-Accessible Oracle
Xingjian Li, Qipeng Liu, Angelos Pelecanos, Takashi Yamakawa
ITCS 2024
arXiv video (by Angelos Pelecanos) - Publicly Verifiable Deletion from Minimal Assumptions.
Fuyuki Kitagawa, Ryo Nishimaki, Takashi Yamakawa
TCC 2023 (soft merge with this paper)
arXiv ePrint video - A New Approach to Post-Quantum Non-Malleability
Xiao Liang, Omkant Pandey, Takashi Yamakawa
FOCS 2023
arXiv, ePrint video (by Xiao Liang) - Obfuscation of Pseudo-Deterministic Quantum Circuits
James Bartusek, Fuyuki Kitagawa, Ryo Nishimaki, Takashi Yamakawa
STOC 2023
also presented at QCRYPT 2023
arXiv, ePrint video (by James Bartusek) - Public Key Encryption with Secure Key Leasing
Shweta Agrawal, Fuyuki Kitagawa, Ryo Nishimaki, Shota Yamada, Takashi Yamakawa
Eurocrypt 2023
arXiv, ePrint video (by Ryo Nishimaki) - From the Hardness of Detecting Superpositions to Cryptography: Quantum Public Key Encryption and Commitments.
Minki Hhan, Tomoyuki Morimae, Takashi Yamakawa
Eurocrypt 2023
also presented at QCW 2022, QIP 2023, and AQIS 2023
arXiv, ePrint video (by Minki Hhan) - Proofs of Quantumness from Trapdoor Permutations
Tomoyuki Morimae, Takashi Yamakawa
ITCS 2023
also presented at QCW 2022
arXiv, ePrint video (by Tomoyuki Morimae) - Bounded Functional Encryption for Turing Machines: Adaptive Security from General Assumptions
Shweta Agrawal, Fuyuki Kitagawa, Anuja Modi, Ryo Nishimaki, Shota Yamada, Takashi Yamakawa
TCC 2022
ePrint video (by Anuja Modi) - Classically Verifiable NIZK for QMA with Preprocessing
Tomoyuki Morimae, Takashi Yamakawa
Asiacrypt 2022
ePrint arXiv video - Verifiable Quantum Advantage without Structure
Takashi Yamakawa, Mark Zhandry FOCS 2022 (Invited to the SIAM Journal on Computing)
also presented at QIP 2023 (plenary talk)
arXiv, ePrint quanta magazine video1 video2 (by Mark Zhandry) - Quantum commitments and signatures without one-way functions
Tomoyuki Morimae, Takashi Yamakawa
CRYPTO 2022
also presented at QCW2022 and QIP 2023
arXiv ePrint video - Post-Quantum Simulatable Extraction with Minimal Assumptions: Black-Box and Constant-Round
Nai-Hui Chia, Kai-Min Chung, Xiao Liang, Takashi Yamakawa
CRYPTO 2022
arXiv ePrint video (by Xiao Liang) - Certified Everlasting Zero-Knowledge Proof for QMA
Taiga Hiroka, Tomoyuki Morimae, Ryo Nishimaki, Takashi Yamakawa
CRYPTO 2022
also presented at QIP 2022 (short plenary talk merged with this paper) and QCRYPT 2022
arXiv ePrint video (by Taiga Hiroka) - Secure Software Leasing from Standard Assumptions
Fuyuki Kitagawa, Ryo Nishimaki, Takashi Yamakawa
TCC 2021
arXiv ePrint video (by Ryo Nishimaki) - On the Impossibility of Post-Quantum Black-Box Zero-Knowledge in Constant Rounds
Nai-Hui Chia, Kai-Min Chung, Qipeng Liu, Takashi Yamakawa
FOCS 2021
also presented at QCRYPT 2021 and QIP 2022 (both merged with A Black-Box Approach to Post-Quantum Zero-Knowledge in Constant Rounds)
arXiv ePrint video - Quantum Encryption with Certified Deletion Revisited: Public Key, Attribute-Based, and Classical Communication
Taiga Hiroka, Tomoyuki Morimae, Ryo Nishimaki, Takashi Yamakawa
Asiacrypt 2021
also presented at QCRYPT2021 and QIP 2022 (merged short plenary talk)
arXiv ePrint video (by Taiga Hiroka)
(A preliminary version appeared as Quantum Encryption with Certified Deletion: Public Key and Attribute-Based ePrint ) - A Black-Box Approach to Post-Quantum Zero-Knowledge in Constant Rounds
Nai-Hui Chia, Kai-Min Chung, Takashi Yamakawa
CRYPTO 2021
also presented at QCRYPT 2021 and QIP 2022 (both merged with On the Impossibility of Post-Quantum Black-Box Zero-Knowledge in Constant Rounds)
arXiv ePrint video - Round-Optimal Blind Signatures in the Plain Model from Classical and Quantum Standard Assumptions
Shuichi Katsumata, Ryo Nishimaki, Shota Yamada, Takashi Yamakawa
Eurocrypt 2021
ePrint video (by Ryo Nishimaki) - Classical vs Quantum Random Oracles
Takashi Yamakawa, Mark Zhandry Eurocrypt 2021
ePrint video
(A preliminary version appeared as A Note on Separating Classical and Quantum Random Oracles. ePrint) - Adaptively Secure Inner Product Encryption from LWE
Shuichi Katsumata, Ryo Nishimaki, Shota Yamada, Takashi Yamakawa
Asiacrypt 2020
ePrint video (by Shota Yamada) - Finding Collisions in a Quantum World: Quantum Black-Box Separation of Collision-Resistance and One-Wayness
Akinori Hosoyamada, Takashi Yamakawa
Asiacrypt 2020 (Best Paper Award)
ePrint video (by Akinori Hosoyamada) - NIZK from SNARG
Fuyuki Kitagawa, Takahiro Matsuda, Takashi Yamakawa
TCC 2020
ePrint video - Classical Verification of Quantum Computations with Efficient Verifier
Nai-Hui Chia, Kai-Min Chung, Takashi Yamakawa
TCC 2020
arXiv ePrint video (by Nai-Hui Chia) - Adaptively Secure Constrained Pseudorandom Functions in the Standard Model
Alex Davidson, Shuichi Katsumata, Ryo Nishimaki, Shota Yamada, Takashi Yamakawa
CRYPTO 2020
ePrint video - Compact NIZKs from Standard Assumptions on Bilinear Maps
Shuichi Katsumata, Ryo Nishimaki, Shota Yamada, Takashi Yamakawa
Eurocrypt 2020
ePrint video (by Shuichi Katsumata) - Quantum Random Oracle Model with Auxiliary Input
Minki Hhan, Keita Xagawa, Takashi Yamakawa
Asiacrypt 2019
ePrint - Adaptively Secure and Succinct Functional Encryption: Improving Security and Efficiency, Simultaneously
Fuyuki Kitagawa, Ryo Nishimaki , Keisuke Tanaka, Takashi Yamakawa
CRYPTO 2019
ePrint - Exploring Constructions of Compact NIZKs from Various Assumptions
Shuichi Katsumata, Ryo Nishimaki, Shota Yamada, Takashi Yamakawa
CRYPTO 2019
ePrint video (by Shuichi Katsumata) - Designated Verifier/Prover and Preprocessing NIZKs from Diffie-Hellman Assumptions
Shuichi Katsumata, Ryo Nishimaki, Shota Yamada, Takashi Yamakawa
Eurocrypt 2019
ePrint video (by Shuichi Katsumata) - (Tightly) QCCA-Secure Key-Encapsulation Mechanism in the Quantum Random Oracle Model
Keita Xagawa, Takashi Yamakawa
PQCrypto 2019
ePrint - Leakage-resilient Identity-based Encryption in Bounded Retrieval Model with Nearly Optimal Leakage-Ratio
Ryo Nishimaki, Takashi Yamakawa
PKC 2019
ePrint - Adaptively Single-key Secure Constrained PRFs for NC1
Nuttapong Attrapadung, Takahiro Matsuda, Ryo Nishimaki, Shota Yamada, Takashi Yamakawa
PKC 2019
ePrint - Tighter Security Proofs for GPV-IBE in the Quantum Random Oracle Model
Shuichi Katsumata, Shota Yamada, Takashi Yamakawa
Asiacrypt 2018. (Invited to Journal of Cryptology)
ePrint - Constrained PRFs for NC1 in Traditional Groups
Nuttapong Attrapadung, Takahiro Matsuda, Ryo Nishimaki, Shota Yamada, Takashi Yamakawa
CRYPTO 2018
ePrint video - Tightly-Secure Key-Encapsulation Mechanism in the Quantum Random Oracle Model
Tsunekazu Saito, Keita Xagawa, Takashi Yamakawa
Eurocrypt 2018
ePrint - Generalized Hardness Assumption for Self-bilinear Map with Auxiliary Information
Takashi Yamakawa, Goichiro Hanaoka, Noboru Kunihiro (non-alphabetical order)
ACISP 2016 - Adversary-Dependent Lossy Trapdoor Function from Hardness of Factoring Semi-smooth RSA Subgroup Moduli
Takashi Yamakawa, Shota Yamada, Goichiro Hanaoka, Noboru Kunihiro (non-alphabetical order)
CRYPTO 2016
ePrint video - A Short Fail-Stop Signature Scheme from Factoring
Takashi Yamakawa, Nobuaki Kitajima, Takashi Nishide, Goichiro Hanaoka, Eiji Okamoto (non-alphabetical order)
ProvSec 2014 - Chosen Ciphertext Security on Hard Membership Decision Groups: The Case of Semi-smooth Subgroups of Quadratic Residues
Takashi Yamakawa, Shota Yamada, Koji Nuida, Goichiro Hanaoka, Noboru Kunihiro (non-alphabetical order)
SCN 2014 - Self-bilinear Map on Unknown Order Groups from Indistinguishability Obfuscation and Its Applications
Takashi Yamakawa, Shota Yamada, Goichiro Hanaoka, Noboru Kunihiro (non-alphabetical order)
CRYPTO 2014. (Invited to Special Issues of Algorithmica)
ePrint video - Reducing Public Key Sizes in Bounded CCA-Secure KEMs with Optimal Ciphertext Length
Takashi Yamakawa, Shota Yamada, Takahiro Matsuda, Goichiro Hanaoka, Noboru Kunihiro (non-alphabetical order)
ISC 2013. - Partially Wildcarded Attribute-based Encryption and Its Efficient Construction
Go Ohtake, Yuki Hironaka, Kenjiro Kai, Yosuke Endo, Goichiro Hanaoka, Hajime Watanabe, Shota Yamada, Kohei Kasamatsu, Takashi Yamakawa, Hideki Imai (non-alphabetical order)
SECRYPT 2013 - Efficient Variants of the Naor-Yung and Dolev-Dwork-Naor Transforms for CCA Secure Key Encapsulation Mechanism
Takashi Yamakawa, Shota Yamada, Takahiro Matsuda, Goichiro Hanaoka, Noboru Kunihiro (non-alphabetical order)
AsiaPKC 2013
- A Note on Output Length of One-Way State Generators and EFIs
Minki Hhan, Tomoyuki Morimae, Takashi Yamakawa
IACR Communications in Cryptology, 2025
arXiv - Finding Collisions in a Quantum World: Quantum Black-Box Separation of Collision-Resistance and One-Wayness
Akinori Hosoyamada, Takashi Yamakawa
Journal of Cryptology, Volume 37, Issue 4, 2024
ePrint - Verifiable Quantum Advantage without Structure
Takashi Yamakawa, Mark Zhandry Journal of the ACM, Volume 71, Issue 3, 2024
arXiv, ePrint - Compact NIZKs from Standard Assumptions on Bilinear Maps
Shuichi Katsumata, Ryo Nishimaki, Shota Yamada, Takashi Yamakawa
Journal of Cryptology, Volume 37, Issue 3, 2024
ePrint - NIZK from SNARGs
Fuyuki Kitagawa, Takahiro Matsuda, Takashi Yamakawa
Journal of Cryptology, Volume 36, Issue 2, 2023
ePrint - Compact Designated Verifier NIZKs from the CDH Assumption without Pairings
Shuichi Katsumata, Ryo Nishimaki, Shota Yamada, Takashi Yamakawa
Journal of Cryptology, Volume 34, 2021
(merged full version of ePrint and ePrint) - Tighter Security Proofs for GPV-IBE in the Quantum Random Oracle Model
Shuichi Katsumata, Shota Yamada, Takashi Yamakawa
Journal of Cryptology, Volume 34, 2021
ePrint - Generic Hardness of Inversion on Ring and Its Relation to Self-Bilinear Map
Takashi Yamakawa, Shota Yamada, Goichiro Hanaoka, Noboru Kunihiro (non-alphabetical order)
Theoretical Computer Science 820, 2020
ePrint - Self-Bilinear Map on Unknown Order Groups from Indistinguishability Obfuscation and Its Applications
Takashi Yamakawa, Shota Yamada, Goichiro Hanaoka, Noboru Kunihiro (non-alphabetical order)
Algorithmica 79(4), 2017
ePrint - Partially Wildcarded Ciphertext-Policy Attribute-Based Encryption and Its Performance Evaluation
Go Ohtake, Kazuto Ogawa, Goichiro Hanaoka, Shota Yamada, Kohei Kasamatsu, Takashi Yamakawa, Hideki Imai (non-alphabetical order)
IEICE Transactions 100-A(9), 2017 - Efficient Key Encapsulation Mechanisms with Tight Security Reductions to Standard Assumptions in the Two Security Models
Yoshikazu Hanatani, Goichiro Hanaoka, Takahiro Matsuda, Takashi Yamakawa (non-alphabetical order)
Security and Communication Networks 9(12), 2016.
- Classically Verifiable (Dual-mode) NIZK for QMA with Preprocessing
Tomoyuki Morimae, Takashi Yamakawa
QCrypt 2021 (online) - A Black-Box Approach to Post-Quantum Zero-Knowledge in Constant Rounds
Nai-Hui Chia, Kai-Min Chung, Takashi Yamakawa
QIP 2021 (online) - Bounded CCA-Secure KEM from the Computational Bilinear Diffie-Hellman Assumption.
Takashi Yamakawa, Shota Yamada, Goichiro Hanaoka, Noboru Kunihiro (non-alphabetical order)
IWSEC 2012 (Best Poster Award)
- Quantum Cryptography and Hardness of Non-Collapsing Measurements
- SG Crypto Workshop, Singapore, Jan, 2026
- A New World in the Depths of Microcrypt: Separating OWSGs and Quantum Money from QEFID
- TQC 2025, Bengaluru, Sep. 2025
- Quantum Advantage from One-Way Functions
- FIT 2025 Top Conference Session, Sapporo (remote talk), Sep. 2025 (In Japanese)
- The Round Complexity of Black-Box Post-Quantum Secure Computation
- CRYPTO 2025, Santa Barbara, Aug. 2025
- On Collision Resistance from Group Actionn
- CFAIL 2025, Santa Barbara, Aug. 2025
- Unclonable Quantum Cryptography
- Computation Kenkyu-kai (Computation Research Meeting), Tokyo, Mar. 2025 (In Japanese)
- A Simple Framework for Secure Key Leasing
- SCIS 2025, Kitakyushu, Jan. 2025 (In Japanese)
- Kyoto Quantum Crypto Workshop, Kyoto, Oct. 2024
- Revocable Quantum Digital Signatures
- TQC 2024, Onna (Okinawa), Sep. 2024
- Quantum Public-Key Encryption with Tamper-Resilient Public Keys from One-Way Functions
- CRYPTO 2024, Santa Barbara, Aug. 2024
- Publicly Verifiable Deletion from Minimal Assumptions
- TCC 2023, Taipei, Dec. 2023
- Quantum Advantage and Cryptography
- 12th Tokei-Butsurigaku-Kondankai (Statistical Physics Casual Talk Meeting), online, Mar. 2025 (In Japanese)
- 10th Quantum Software Kenkyu-Happyo-Kai (Quantum Software Research Presentation Meeting), Kyoto, Oct. 2023 (In Japanese)
- 6th Kanazawa Angou-Riron-Benkyou-Kai (Kanazawa Cryptography Study Meeting), Kanazawa, Aug. 2023 (In Japanese)
- Classical vs Quantum Advice and Proofs under Classically-Accessible Oracle
- 11th Tokyo Crypto Day, Dec. 2023
- YITP Seminar, Kyoto, Jul. 2023
- Quantum Advantage from Cryptographic Assumptions
- 2023 EWHA-KMS International Workshop on Cryptography, Seoul, Jul. 2023
- Quantum Public-Key Encryption with Tamper-Resilient Public Keys from One-Way Functions
- QIT 48, Kyoto, May. 2023 (In Japanese)
- Non-uniformity and Quantum Advice in the Quantum Random Oracle Model (proxy for Qipeng Liu)
- Eurocrypt 2023, Lyon, Apr. 2023
- Classically Verifiable NIZK for QMA with Preprocessing
- Asiacrypt 2022, Taipei, Dec. 2022
- Proofs of Quantumness from Trapdoor Permutations
- QCW 2022, Taipei, Dec. 2022
- Verifiable Quantum Advantage Without Structure
- Shonan Meeting "New Directions in Provable Quantum Advantages", Shonan, Dec. 2023
- Quantum Innovation 2023, Tokyo, Nov. 2023
- Theory Seminar, Taipei, May 2023
- CS Seminar at CQT, online, May 2023
- QIP 2023, Ghent, Jan. 2023
- FOCS 2022, Denver, Nov. 2022
- Third Kyoto Workshop on Quantum Information, Computation, and Foundations, online, Oct. 2022
- Recent Devolpments in Complexity-based Quantum Cryptography
- Mathematics of Post-Quantum Cryptography and Quantum Information, Fukuoka, Aug. 2022 video (In Japanese)
- Quantum commitments and signatures without one-way functions
- CRYPTO 2022, Santa Barbara, Aug. 2022
- Ben-Gurion University CS Seminar, online, May 2022
- On the Impossibility of Post-Quantum Black-Box Zero-Knowledge in Constant Rounds
- FOCS 2021, online, Feb. 2022
- Quantum Computation and Cryptography
- Information Mathematics Seminar, the University of Tokyo, Tokyo, Dec. 2023 (in Japanese)
- Information Mathematics Seminar, the University of Tokyo, Tokyo, Dec. 2022 (in Japanese)
- ISEC Seminar, online, Nov. 2022 (in Japanese)
- YITP Seminar, online, Dec. 2021 (in Japanese)
- Classical vs Quantum Random Oracles.
- ENS de Lyon, RHUL, and CWI Joint Online Crypto Seminar, online, Mar. 2022
- Eurocrypt 2021, online, Dec. 2021
- Workshop on Cryptography and Information Security 2021, online, Sep. 2021 (In Japanese)
- On Post-Quantum Black-Box Zero-Knowledge in Constant Rounds
- Second Kyoto Workshop on Quantum Information, Computation, and Foundation, online, Sep. 2021
- QCRYPT 2021, online, Aug. 2021
- A Black-Box Approach to Post-Quantum Zero-Knowledge in Constant Rounds
- CRYPTO 2021, online, Aug. 2021
- Classical Verification of Quantum Computations with Efficient Verification
- QIT 44, online, May 2021
- NIZK from SNARG
- TCC 2020, online, November 2020.
- UC Berkeley Crypto Seminar, online, August 2020.
- Adaptively Secure Constrained Pseudorandom Functions in the Standard Model.
- CRYPTO 2020, online, August 2020.
- Introduction to post-quantum public key cryptography and zero-knowledge.
- The 3rd YITP Quantum Information School, online, July 2020. (In Japanese)
- Finding Collisions in a Quantum World: Quantum Black-Box Separation of Collision-Resistance and One-Wayness.
- ENS de Lyon, RHUL, and CWI Joint Online Crypto Seminar, online, July 2021
- Joint Workshop of NTT Labs (Japan) and NTT Research (USA), Kyoto, December 2019.
- Theory Day in Taiwan (2019), Taipei, October 2019.
- Adaptively Single-key Secure Constrained PRFs for NC1.
- PKC 2019, Beijing, April 2019
- Leakage-Resilient Identity-Based Encryption in Bounded Retrieval Model with Nearly Optimal Leakage-Ratio.
- PKC 2019, Beijing, April 2019
- Towards Ideal Self-bilinear Map.
- The 5th ACM ASIA Public-Key Cryptography Workshop, June 2018 (Invited)
- Tightly-Secure Key-Encapsulation Mechanism in the Quantum Random Oracle Model.
- Eurocrypt 2018, Tel Aviv, May 2018
- ISEC Seminar, Sapporo, July 2018 (In Japanese)
- Constrained PRFs for NC1 in Traditional Groups.
- Tokyo Crypto Day, Tokyo, March. 2018
- CRYPTO 2018, Santa Barbara, Aug. 2018
- ISEC Seminar, Tokyo, Sep. 2018 (In Japanese)
- Adversary-dependent Lossy Trapdoor Function from Hardness of Factoring Semi-smooth RSA Subgroup Moduli.
- CRYPTO 2016, Santa Barbara, Aug. 2016
- ISEC Seminar, Hiroshima, Dec. 2016 (In Japanese)
- 10-th Workshop on Secure Constructions and Applications of Public Key Cryptography, Tokyo, Feb. 2017 (In Japanese)
- Generalized Hardness Assumption for Self-bilinear Map with Auxiliary Information.
- ACISP 2016, Melbourne, July 2016
- Applications of Indistinguishability Obfuscation.
- IEICE General Conference, Shiga, Mar. 2015 (In Japanese)
- A Short Fail-Stop Signature Scheme from Factoring.
- ProvSec 2014, Hong Kong, Oct. 2014
- Chosen Ciphertext Security on Hard Membership Decision Groups: The Case of Semi-smooth Subgroups.
- SCN 2014, Amalfi, Sep. 2014
- Self-bilinear Map on Unknown Order Groups from Indistinguishability Obfuscation and Its Applications.
- CRYPTO 2014, Santa Barbara, Aug. 2014
- ISEC Seminar, Tokyo, Dec. 2014 (In Japanese)
- 8-th Workshop on Secure Constructions and Applications of Public Key Cryptography, Tokyo, Feb. 2015 (In Japanese)
- Reducing Public Key Sizes in Bounded CCA-Secure KEMs with Optimal Ciphertext Length.
- ISC 2013, Dallas, Nov. 2013
- Chosen Ciphertext Secure Encryption over Semi-smooth Subgroup Revisited.
- IWSEC 2013, SCIS/CSS Invited Session, Okinawa, Nov. 2013 (Invited)
I have worked / am working with the following internship students:
- Yuki Shirakawa from Kyoto University (2025.08-2025.09)
- Manasi Shingane from University of Maryland (2025.06-2025.08)
- Mohammed Barhoush from University of Montreal (2024.09-2025.01)
- Taiga Hiroka from Kyoto University (2023.08-2023.09)
- Minki Hhan from Seoul National University (2018.10 - 2019.1)
Fall 2021, YITP Intensive Lecture 1 (on (quantum) cryptography) , Yukawa Institute of Theoretical Physics, Kyoto University (In Japanese)
Program Committee Member:
Cryptography:
Asiacrypt: 2021, 2022, 2023, 2025
CRYPTO: 2026
TCC: 2023, 2024, 2025
ITC: 2023
PQCRYPTO: 2025
CFail: 2025
QCW: 2022
APKC: 2018, 2019
Quantum:
QIP: 2023
TQC: 2023, 2025
AQIS: 2025
QCRYPT: 2023, 2024, 2025
Conference Subreview : Asiacrypt, CRYPTO, Eurocrypt, PKC, TCC, ACISP, ACNS, FOCS, ISAAC, ISITA, ITC, ITCS, IWSEC, MFCS, Provsec, SCN, STOC, TQC, QCRYPT, QIP etc.
Journal Review: Designs, Codes and Cryptography, Nature Physics, Quantum, etc.
- Maejima Hisoka Encouragement Award, Feb. 2026
- SCIS Innovation Paper Award at SCIS 2025 (Japanese domestic symposium)
- for the paper: 安全な量子鍵貸与のためのシンプルなフレームワーク (A Simple Framework for Secure Key Leasing) (with Fuyuki Kitagawa and Tomoyuki Morimae)
- Asiacrypt 2020 Best Paper Award
- for the paper: Finding Collisions in a Quantum World: Quantum Black-Box Separation of Collision-Resistance and One-Wayness (with Akinori Hosoyamada).
- Dean's Award for Outstanding Achievement from Graduate School of Frontier Science (Ph.D) (top honor in the department), The University of Tokyo, March 2017.
- Tsujii Shigeo Security Student Award, 2015.
- for the paper: Self-bilinear Map on Unknown Order Groups from Indistinguishability Obfuscation and Its Applications (with Shota Yamada, Goichiro Hanaoka, Noboru Kunihiro, CRYPTO 2014).
- Dean's Award for Outstanding Achievement from Graduate School of Frontier Science (Master) (top honor in the department), The University of Tokyo, March 2014.
- SCIS Paper Award at SCIS 2013 (Japanese domestic symposium)
- for the paper: 素因数分解問題に基づくSemi-smooth部分群上のCCA安全な公開鍵暗号の安全性証明について (On Security Proof of CCA-Secure Public Key Encryption in Semi-Smooth Subgroups) (with Shota Yamada, Goichiro Hanaoka, Noboru Kunihiro)
- IWSEC 2012 Best Poster Award.
- for the poster: Bounded CCA-Secure KEM from the Computational Bilinear Diffie-Hellman Assumption (with Shota Yamada, Goichiro Hanaoka, Noboru Kunihiro)
- Othello: A two-player strategy board game popular in Japan, I've been playing since 2002. I'm currently ranked 9th at World Othello Federation Ratings (March 2025).
You can learn the rule and basic strategies from a free e-book written by a former world champion Brian Rose here. - Other board games including Go, Shogi (Japanese Chess), Backgammon etc.
- Listening to classical music and playing the piano.
- Learning languages.