*Please call me "Shu" for short. Pronounced exactly like "shoe".
I'm a lead cryptography researcher at PQShield Ltd, U.K, working from Japan. Before that, I was a senior cryptography researcher at the National Institute of Advanced Industrial Science and Technology (AIST), Japan (and also a research consultant at PQShield Ltd, U.K.).
My main research topics include, but are not limited to, lattice-based (or more generally post-quantum) cryptography. I enjoy constructing and providing security analysis of cryptographic primitives/protocols such as various types of signature and encryption schemes (e.g., ring signatures, IBE/ABE), zero-knowledge proofs, and secure messaging protocols.
I'm always thrilled, excited, and motivated to discuss any interesting problems with others so please feel free to reach out to me!!
Also, PQShield is hiring so if you're interested either as a permanent researcher, post-doc, or intern, check out PQShield's career webpage or contact me directly.
Contact: shuichi.katsumata [at] pqshield.com OR shuichi.katsumata000 [at] gmail.com
Real World Crypto 2023. (A version of [HKP22@CCS]. ePrint.)
ACM CCS 2022. ePrint.
A New Framework For More Efficient Round-Optimal Lattice-Based (Partially) Blind Signature via Trapdoor Sampling. Rafael del Pino, Shuichi Katsumata.
CRYPTO 2022. ePrint.
EUROCRYPT 2022. ePrint.
Exposing Private User Behaviors of Collaborative Filtering via Model Inversion Techniques. Seira Hidano, Takao Murakami, Shuichi Katsumata, Shinsaku Kiyomoto, Goichiro Hanaoka.
PETS/PoPETS 2020. Proceedings.
ESORICS 2019. ePrint.
Group Signatures without NIZK: From Lattices in the Standard Model. Shuichi Katsumata, Shota Yamada.
EUROCRYPT 2019. ePrint.
Non-Zero Inner Product Encryption Schemes from Various Assumptions: LWE, DDH and DCR. Shuichi Katsumata, Shota Yamada.
PKC 2019. ePrint.
PKC 2019. ePrint.
ASIACRYPT 2018. (Invited to Journal of Cryptography.) ePrint.
Attribute-Based Signatures for Unbounded Languages from Standard Assumptions. Yusuke Sakai, Shuichi Katsumata, Nuttapong Attrapadung, Goichiro Hanaoka.
ASIACRYPT 2018. ePrint.
Attribute-Based Signatures for Unbounded Circuits in the ROM and Efficient Instantiations from Lattices. Ali El Kaafarani, Shuichi Katsumata.
PKC 2018. ePrint.
Anonymous Reputation Systems Achieving Full Dynamicity from Lattices. Ali El Kaafarani, Shuichi Katsumata, Ravital Solomon.
FC 2018. Preproceeding.
On the Untapped Potential of Encoding Predicates by Arithmetic Circuits and Their Applications. Shuichi Katsumata.
Model Inversion Attacks for Prediction Systems: Without Knowledge of Non-Sensitive Attributes. Seira Hidano, Takao Murakami, Shuichi Katsumata, Shinsaku Kiyomoto, Goichiro Hanaoka.
PST 2017. Proceedings.
Partitioning via Non-linear Polynomial Functions: More Compact IBEs from Ideal Lattices and Bilinear Maps. Shuichi Katsumata, Shota Yamada.
Robust Cost Sensitive Support Vector Machine. Shuichi Katsumata, Akiko Takeda.
AISTATS 2015. Proceedings.
Constructing Subspace Membership Encryption through Inner Product Encryption. Shuichi Katsumata, Noboru Kunihiro.
ProvSec 2014. Proceedings.
Designs, Codes and Cryptography, 2023. Springer. To appear. (Full version of [BKP20@AC]
Direct Computation of Branching Programs and its Applications to More Efficient Lattice-based Cryptography. Shuichi Katsumata, Toi Tomita, Shota Yamada.
Designs, Codes and Cryptography, 2022. Springer.
Journal of Cryptology, Volume 35, 2022. Springer. (Full version of [HKKP22@PKC]).
Theoretical Computer Science, Volume 900, 2021. Elsevier. (Full version of [EKW19@ESORICS]).
Compact Designated Verifier NIZKs from the CDH Assumption Without Pairings. Shuichi Katsumata, Ryo Nishimaki, Shota Yamada, Takashi Yamakawa.
Journal of Cryptology, Volume 34, 2021. Springer. (Merged and revised version of [KNYY19@EC] and [KNYY19@C]).
Journal of Cryptology, Volume 34, 2021. Springer. (Full version of [KYY18@AC]).
Theoretical Computer Science, Volume 809, 2020. Elsevier. (Full version of [KMT19@PKC]).
IEICE Transactions E101-D(11), 2018. (Full version of [HMKKH18@PST]).
IEICE Transactions E100-A(9), 2017. (Full version of [KK14@ProvSec]).
Post-Quantum Cryptography and Secure Messaging.
MIT Technology Review: Innovators Under 35 Japan Summit 2022 in Nihonbashi, December, 2022.
A Survey on the NIST PQC Standardization (耐量子計算暗号の標準化動向).
Hardware Security Forum, December, 2022.
Secure Messaging in a Post-Quantum World.
PQShield Webinar, November, 2022.
Revisiting Fuzzy Signatures: Towards a More Risk-Free Cryptographic Authentication System based on Biometrics.
21th Forum on Information Technology, September, 2022.
A New Simple Technique to Bootstrap Various Lattice Zero-Knowledge Proofs to QROM Secure NIZKs.
Monash Univsersity, Cybersecurity Seminars, July, 2021. (slides, video).
Workshop on Cryptography and Information Security (WCIS), September, 2021.
Design and Evaluation for New-generation Cryptography, November. 2021.
Calamari and Falafl: Logarithmic (Linkable) Ring Signatures from Isogenies and Lattices.
ENS de Lyon/Royal Holloway/CWI Cryptography Seminar, March, 2021. (slides).
Compact NIZKs from Various Assumptions.
MPI/RUB Seminar, December, 2020. (slides).
Exploring Constructions of Compact NIZKs from Various Assumptions.
Workshop on Cryptography and Information Security (WCIS), September, 2019. (slides).
Lattice IBE without Reduction Loss in the Random Oracle Model.
SCIS/CSS Invited Session in IWSEC, September, 2016.
CRYPTO, EUROCRYPT, ASIACRYPT, TCC, PKC, AsiaCCS, ACNS, PQCrypto, ACISP, APKC, IWSEC, DCC, etc...
Local Organizing Committee
Senior researcher at the National Institute of Advanced Industrial Science and Technology (AIST).
Cryptography research consultant at PQShield.
MIT Technology Review, Innovators Under 35 Japan, 2022. Japanese Website. English Website (coming soon).
Symposium on Cryptography and Information Security 2021 (SCIS 2021), Best Paper Award (received by Keitaro Hashimoto)
& Tsujii Shigeo Security Award, 2021.
- for the paper: An Efficient and Generic Construction for Signal’s Handshake (X3DH): Post-Quantum, State Leakage Secure, and Deniable. (with Keitaro Hashimoto, Kris Kwiatkowski, Thomas Prest.)
Dean's Award for Outstanding Achievement from Graduate School of Frontier Science (Ph.D) (top honor in the department), The University of Tokyo. May, 2019.
Invited to Journal of Cryptography from ASIACRYPT 2018.
Computer Security Symposium 2017 (CSS2017), Best Student Paper Award.
& Tsujii Shigeo Security Award, 2018.
- for the paper: On the Untapped Potential of Encoding Predicates by Arithmetic Circuits and Their Applications.
Research Fellowships for Doctoral Scientists, Japan Society for the Promotion of Science (JSPS). 2017.
Symposium on Cryptography and Information Security 2016 (SCIS 2016), Best Paper Award.
& Tsujii Shigeo Security Award, 2017.
- for the paper: Partitioning via Non-linear Polynomial Functions: More Compact IBEs from Ideal Lattices and Bilinear Maps. (with Shota Yamada.)