Takashi Yamakawa
(山川高志)
I am a research scientist at NTT, Japan. My main research area is (post-quantum) cryptography.
Current Position
Distinguished Researcher at NTT Social Informatics Laboratories (formerly Secure Platform Laboratories)
Affiliate Associate Professor at Yukawa Institute for Theoretical Physics, Kyoto University
Experience
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)
Education
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)
Publications
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. )
Preprint
Verifiable Quantum Advantage without Structure. Takashi Yamakawa, Mark Zhandry, arXiv, ePrint
Bounded Functional Encryption for Turing Machines: Adaptive Security from General Assumptions. Shweta Agrawal, Fuyuki Kitagawa, Anuja Modi, Ryo Nishimaki, Shota Yamada, Takashi Yamakawa ePrint
Classically Verifiable NIZK for QMA with Preprocessing. Tomoyuki Morimae, Takashi Yamakawa arXiv
International Conferences
Quantum commitments and signatures without one-way functions. Tomoyuki Morimae, Takashi Yamakawa, CRYPTO 2022 arXiv ePrint
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
Certified Everlasting Zero-Knowledge Proof for QMA. Taiga Hiroka, Tomoyuki Morimae, Ryo Nishimaki, Takashi Yamakawa, CRYPTO 2022 arXiv ePrint
Secure Software Leasing from Standard Assumptions. Fuyuki Kitagawa, Ryo Nishimaki, Takashi Yamakawa, TCC2021, 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, QCRYPT 2021 (merged), QIP 2022 (merged) 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, QCRYPT2021, QIP 2022 (merged short plenary talk) arXiv ePrint video (by Taiga Hiroka)
(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, QCRYPT 2021 (merged), QIP 2022 (merged) 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
(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.
Journal Articles
Compact Designated Verifier NIZKs from the CDH Assumption without Pairings. Shuichi Katsumata, Ryo Nishimaki, Shota Yamada, Takashi Yamakawa, Journal of Cryptology, to be published, 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.
Posters
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)
Talks
Quantum commitments and signatures without one-way functions.
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
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. (耐量子公開鍵暗号入門・耐量子ゼロ知識証明入門)
The 3rd YITP Quantum Information School (第三回基研量子情報スクール), 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. (識別不可性難読化の応用)
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)
Lectures
Fall 2021, YITP Intensive Lecture 1 (on (quantum) cryptography) , Yukawa Institute of Theoretical Physics, Kyoto University (In Japanese)
Activities
Program Committee Member: Asiacrypt 2021, APKC 2019, APKC 2018
Subreviewer : Asiacrypt, CRYPTO, Eurocrypt, PKC, TCC, ACISP, ACNS, ISITA, IWSEC, Provsec, SCN, etc.
Awards
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 conference).
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)
Hobbies
Othello: A two-player strategy board game popular in Japan, I've been playing since 2002. I'm currently ranked 5th at World Othello Federation Ratings (Apr. 2020).
You can learn the rule and basic strategies from a free e-book written by a former world champion Brian Rose here.I'm also a fan of other board games including Go, Shogi (Japanese Chess), Backgammon etc.
Contact Information
Please send official invitation emails (PC member, talks, etc. ) to: takashi.yamakawa.ga@hco.ntt.co.jp
For other emails (review request, question/comment on paper, etc.): takashi.yamakawa.obf@gmail.com