About me
Hi!
My name is Wonseok Choi (최원석, 崔元碩), a Post-Doc @ The Purdue Blockchain Lab hosted by Vassilis Zikas. I am currently involved in multiple projects, focusing on two main areas: 1) mathematical analysis of algorithms and protocols and 2) designing algorithms and protocols for multi-party computation, blockchain, etc. Previously, I was a research fellow at KIAS (Korea Institute for Advanced Study) for a half year, mentored by Changmin Lee.
I received my Ph.D. from KAIST (Korea Advanced Institute of Science and Technology), where I was fortunate to be advised by Jooyoung Lee. During my Ph.D., I focused on provable security in symmetric-key cryptography: improving security analyses of several symmetric-key algorithms and proposing new constructions such as pseudorandom functions, message authentication codes, and authenticated encryptions with associated data.
Before studying cryptography, I majored in mathematics at KAIST for my master’s and bachelor’s degrees. I still enjoy solving math quizzes!
My research interests include
Cryptography including symmetric-key, public-key, primitive design, and provable security
Secure multi-party computation and blockchain
Related topics in cryptology and mathematics
Latest News
(Apr. 2024) I am planning to visit the University of Cincinnati during the third week of this month to collaborate with Seungki Kim.
(Mar. 2024) I talked at Digital Security Group, Radboud University and FSE 2024 about building PRFs from TPRPs.
(Jan. 2024) My paper on constructing PRFs from tweakable PRPs was accepted to ToSC 2024(1) / FSE 2024.
(Dec. 2023) I talked at ASK 2024 and DESILO about fine-tuning overidealized ideal worlds.
Publication List
Wonseok Choi, Jooyoung Lee, and Yeongmin Lee, “Building PRFs from TPRPs: Beyond the Block and the Tweak Length Bounds”, ToSC 2024(1) / FSE 2024.
Yu Long Chen, Wonseok Choi, and Changmin Lee, “Improved Multi-User Security Using the Squared-Ratio Method”, CRYPTO 2023.
Wonseok Choi, Hwigyeom Kim, Jooyoung Lee, and Yeongmin Lee, “Multi-User Security of the Sum of Truncated Random Permutations”, ASIACRYPT 2022.
Wonseok Choi, Byeonghak Lee, Jooyoung Lee, and Yeongmin Lee, “Toward a Fully Secure Authenticated Encryption Scheme From a Pseudorandom Permutation”, ASIACRYPT 2021.
Wonseok Choi, Akiko Inoue, Byeonghak Lee, Jooyoung Lee, Eik List, Kazuhiko Minematsu, and Yusuke Naito, “Highly Secure Nonce-based Macs from the Sum of Tweakable Block Ciphers”, ToSC 2020(4) / FSE 2022.
Wonseok Choi, Byeonghak Lee, Yeongmin Lee, and Jooyoung Lee, “Improved Security Analysis for Nonce-based Enhanced Hash-then-Mask MACs”, ASIACRYPT 2020.
Jincheol Ha, Seongkwang Kim, Wonseok Choi, Jooyoung Lee, Dukjae Moon, Hyojin Yoon, and Jihoon Cho, “Masta: An HE-friendly Cipher Using Modular Arithmetic”, IEEE Access 2020.
Wonseok Choi, Byeonghak Lee, and Jooyoung Lee, “Indifferentiability of Truncated Random Permutations”, ASIACRYPT 2019.
Grants
Sejong Science Fellowship (140 million KRW, Sep. 2023 - Aug. 2025)
“Building Efficient Symmetric-Key Primitives for Secure Multi-Party Computation”
Supported by National Research Foundation of Korea (NRF) grant funded by the Korea government (MSIT)
KIAS Individual Grant (22.5 million KRW, Sep. 2022 - Mar. 2023)
“Designing and Analysis of Cryptographic Pseudorandom Functions”
Supported by Korea Institute for Advanced Study
*1 million KRW ≈ 800 USD
Editorial Board / Program Committee
ISC 2024
ToSC 2024/2025 / FSE 2025
ToSC 2023/2024 / FSE 2024
Talks
“On Overidealizing Ideal Worlds: Xor of Two Permutations and its Applications”
Invited Talk at Radbound University, Nijmegen (the Netherlands), Mar. 2024.
Invited Talk at DESILO, Seoul (Korea), Dec. 2023.
Invited Talk at ASK 2023, Guangzhou (China), Dec. 2023.
“Improved Multi-User Security Using the Squared-Ratio Method”
CRYPTO 2023, Santa Barbara (CA), Aug. 2023.
Athecrypt 2023, Athens (Greece), May. 2023.
Invited Talk at NEC Core Technology Forum, Kanagawa (Japan), Dec. 2022.
“Multi-User Security of the Sum of Truncated Random Permutations”
ASIACRYPT 2022, Taipei (Taiwan), Dec. 2022.
2022 Global KMS International Conference, Seoul (Korea), Oct. 2022.
“Building PRFs from TPRPs: Beyond the Block and the Tweak Length Bounds”
FSE 2024, Leuven (Belgium), Mar. 2024.
2022 KMS Spring Meeting, Online, Apr. 2022.
Security@KAIST Student Research Presentation, Online, Nov. 2021.
National Cryptography Contest Awards, Seoul (Korea), Oct. 2021.
“Indifferentiability of Truncated Random Permutations”
ASIACRYPT 2019, Kobe (Japan), Dec. 2019.
Invited Talk at Korea Cryptography Forum Workshop, Gyeonggi (Korea), May. 2019.
National Cryptography Contest Awards, Seoul (Korea), Nov. 2018.
Reviews
Review: ISC 2024, FSE 2025 (ToSC 2024/2025), FSE 2024 (ToSC 2023/2024)
Subreview: CRYPTO 2024, EUROCRYPT 2024, ACNS 2023, EUROCRYPT 2023, and Latincrypt 2023
External Review: FSE 2022, ASIACRYPT 2020, ASIACRYPT 2019, ICISC 2018, and ProvSec 2018
Last Update: 2/APR/2024