Wonseok Choi

Wonseok Choi

Assistant Professor, Cryptographer

Wonseok’s Homepage

I am Wonseok Choi (최원석, 崔元碩), an assistant professor in the EECS department at DGIST, Korea.

My research interests include the theory of cryptography and related topics in cryptology and mathematics. I aim to establish precise security models or requirements for each problem, define appropriate notions, and conduct thorough analyses.

I was a postdoc at Purdue University and Georgia Tech, working with Vassilis Zikas. My postdoctoral research focused on Byzantine fault-tolerant protocols and on various applications of cryptography, such as digital signatures, blockchain, anamorphic encryption, and secure messaging. Before that, I was a research fellow at KIAS, where I worked on symmetric-key cryptography and provable security methodologies, mentored by Changmin Lee.

I received my Ph.D. from KAIST, where I was advised by Jooyoung Lee. During my Ph.D., I focused on provable security in symmetric-key cryptography. My thesis was titled “Study on Building Pseudorandom Functions from Cryptographic Primitives.”

I lead the Cryptology and Information Security Lab at DGIST. Our research focuses on:

  1. Security analysis and proofs of cryptographic algorithms and protocols;

  2. Design of algorithms and protocols for multi-party computation, blockchain, and related areas; and

  3. AI security and privacy

Visits and Internships. I am happy to host visitors at DGIST, from students to senior researchers, for stays of a few days to several months. If you are a prospective student with a strong math/theoretical CS background, I recommend starting with an undergraduate internship before applying to graduate school.

Post-Doc Opening. There is one postdoctoral position available supported by the AI Star Fellowship project. The successful candidate will work on topics in AI security and privacy and collaborate with other faculty members in the project. Candidates must have publications at top cryptography or security venues (CRYPTO, EUROCRYPT, ASIACRYPT, CCS, IEEE S&P, USENIX Security). We may also consider exceptional candidates with publications on relevant topics at top AI venues.

Latest News

(Oct. 2026) Prof. Changmin Lee and I were awarded the DGIST-Korea University Co-Seed Funding for Cryptographic Consensus Protocols for Physical AI.

(Sep. 2026) I was selected as one of 10 researchers on an AI Star Fellowship project (MSIT/IITP; 11 billion KRW over 6 years)

(Jul. 2026) I organized and ran the DGIST Crypto Summer Camp during the first week of July! Prof. Youngsik Kim’s PAC Lab@DGIST helped A LOT. Changmin, Minki, Seongkwang, Yeongmin, and Jincheol gave lectures, and students from DGIST, KAIST, and Korea University actively participated. Thank you all so much! I plan to hold the event annually and make it more public and accessible (this time it was invitation-only and in Korean). I hope we can meet enthusiastic students again next year.

(May 2026) Our paper on anamorphic encryption was accepted at CRYPTO 2026!

(Mar. 2026) I gave an invited talk at ASK 2026 and attend FSE 2026. Update: We, the GAPS organizers, were awarded the most chewing gum-ish talk prize during the FSE 2026 rump session!

(Mar. 2026) I was awarded the Outstanding Young Scientist Grant to develop a unified framework for the concrete security of MPC.

(Jul. 2025) Our paper on sharp anonymous multisignatures, co-authored with Xiangyu and Vassilis, was accepted at AFT 2025.

Professional Activities

Organizer

Program Committee

  • FSE 2024-2027
  • ISC 2024-2026
  • ASIACRYPT 2024

Teaching and Advising

Courses

  • DGIST IC638c Introduction to Cryptography (2026 Fall)
  • DGIST CSE405 Computer Security (2026 Spring)
  • DGIST CSE301 Computer Algorithms (2025 Fall)

Post-Docs

  • Mincheol Son (formerly a PhD student at KAIST, co-supervised with Prof. Youngsik Kim)
  • Sunyeop Kim (starting in December, co-supervised with Prof. Youngsik Kim)
  • Abishanka Saha (starting in January)

PhD Students

  • Wookjin Choi (formerly an assistant professor at Kyoto University)

Co-supervised PhD Students

  • Won Kim (Korea University; co-supervised with Prof. Changmin Lee)

Publication List

  • Wonseok Choi, Daniel Collins, Xiangyu Liu, Roy Stracovsky, and Vassilis Zikas, “A Unified Treatment of Anamorphic Encryption”, CRYPTO 2026.

  • Wonseok Choi, Xiangyu Liu, and Vassilis Zikas, “Blockchain Governance via Sharp Anonymous Multisignatures”, AFT 2025.

  • Alexandre Adomnicăi, Wonseok Choi, Yeongmin Lee, Yusuke Naito, and Kazuhiko Minematsu, “Cymric: Short-tailed but Mighty”, TCHES 2025(3) / CHES 2025.

  • Wonseok Choi, Jooyoung Lee, and Yeongmin Lee, “Toward Full n-bit Security and Nonce Misuse Resistance of Block Cipher-based MACs”, ASIACRYPT 2024.

  • Ritam Bhaumik, Wonseok Choi, Avijit Dutta, Cuauhtemoc Mancillas Lopez, Hrithik Nandi, and Yaobin Shen, “Efficient Variants of TNT with BBB Security”, ProvSec 2024.

  • Wonseok Choi, Seongha Hwang, Byeonghak Lee, and Jooyoung Lee, “ZLR: A Fast Online Authenticated Encryption Achieving Full Security”, DCC 2024.

  • Ritam Bhaumik, Bishwajit Chakraborty, Wonseok Choi, Avijit Dutta, Jérôme Govinden, and Yaobin Shen, “The Committing Security of MACs with Applications to Generic Composition”, CRYPTO 2024.

  • 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.

Last Update: 20/OCT/2026