About us

We are Cryptology & Algorithm Lab and our leader is Professor Jae Hong Seo. Our main research interests are in cryptography especially zero-knowledge proof. Besides cryptography, we’re interested in artificial intelligence using deep learning such as face recognition and speaker recognition.

Annual News

Grant Aug 30, 2026

The following project supported by the National Research Foundation of Korea (NRF) has been selected, and will start in September 2026.

Foundations of Certifiably Robust AI against Adversarial Attacks

Member Aug 27, 2026

Sunpill Kim, our lab’s Ph.D. graduate and postdoctoral researcher, will join the Division of Computer Science at Sookmyung Women’s University as an Assistant Professor, starting September 2026.

Conference Jun 20, 2026

Accepted for publication at ECCV 2026.

Changjin Kim, Seunghun Paik, Dongsoo Kim, and Jae Hong Seo*
Breaking High Confidence: Practical Face Impersonation under High-Security Thresholds

Talk Jun 12, 2026

Prof. Taeho Jung from the Department of Computer Science and Engineering, University of Notre Dame will give an invited lecture at the C&A Lab.

Date & Place: 01:00 PM, Jun 15 / Natural Science Building 702
Title: The Future of Practical Cryptography — PIR & TEE

Journal Jun 11, 2026

Accepted for publication at IEEE Signal Processing Letters.

Seunghun Paik†, Chanwoo Hwang†, and Jae Hong Seo*
Toward Generating Unlearnable Examples for Open-Set Face Recognition

Grant Jun 5, 2026

Sunpill Kim (postdoc) and Minsu Kim (graduate student) have been selected for the AI Seoul Tech Research Support Project 2026, by the Seoul Future Foundation (Seoul Metropolitan Government).

Talk May 31, 2026

Prof. Taechan Kim from the Department of Artificial Intelligence, Gachon University will give an online lecture to the C&A Lab.

Date & Place: 04:00 PM, Jun 1 / Online (Zoom)
Title: Invisible Image Watermarks: From Pixel-level to Semantic Watermark

Talk May 23, 2026

Prof. Taeho Jung from the University of Notre Dame will visit the C&A Lab for an academic exchange and research collaboration.

Date & Place: 01:00 PM, May 29 / Natural Science Building 702

Talk May 20, 2026

Prof. Yongha Son from Sungshin Women’s University will visit the C&A Lab and give a lecture.

Date & Place: 01:30 PM, May 21 / Natural Science Building 102
Title: Private Set Intersection

Member May 4, 2026

Two undergraduate students Hyeonmin Jang and Ingeun Yun joined our Cryptology & Algorithm Lab. We are delighted to welcome them.

Talk Apr 20, 2026

Dr. Keewoo Lee from the Ethereum Foundation visited the C&A Lab and gave a lecture.

Date & Place: 01:00 PM, Apr 20 / Natural Science Building 702
Title: Private Information Retrieval

Journal Apr 13, 2026

Accepted for publication at IEEE Access.

Minsu Kim†, Seunghun Paik†, Seongae Baek, Sangyoon Shin, Sunpill Kim, and Jae Hong Seo*
SilverMask: Face Template Protection with Fine-Grained Noise Correction

Conference Apr 10, 2026

Accepted for publication at ACM CCS 2026.

Seunghun Paik†, Sunpill Kim†, Chanwoo Hwang, and Jae Hong Seo*
Casting the Net! Revisiting MasterFace Impersonation Attacks

Program Apr 9, 2026

Yunki Kim has been selected for the National Cryptographic Expert Training Program (NACET) 12th cohort.

Award Apr 3, 2026

Selected Outstanding Paper at Hanyang University.

Seunghun Paik, Chanwoo Hwang, Sunpill Kim, and Jae Hong Seo*
On the Reversibility of Locality-Sensitive Hashing-Based Biometric Template Protections
IEEE Transactions on Dependable and Secure Computing

Workshop Mar 18, 2026

C&A Lab hosted the “MATH: Make AI Trust Higher” workshop at Hanyang University. View poster

Award Feb 5, 2026

Sunpill Kim will receive the Outstanding Ph.D. Dissertation Award from Hanyang University.

Sunpill Kim
Score-Based Non-Adaptive Attack Against Face Recognition Systems

Journal Jan 13, 2026

Accepted for publication at IEEE Access.

Hyeonbum Lee, Seunghun Paik, Hyunjung Son, and Jae Hong Seo*
Cougar: Cubic Root Verifier Inner Product Argument under Discrete Logarithm Assumption

Member Jan 5, 2026

Insoo Kim (undergraduate student) joined Cryptology & Algorithm Lab, and we are pleased to welcome him to our Lab.

Seminar

Interested in joining the lab? ↗

2026 · Summer · Trustworthy FRS

7 sessions

Jul 8 · 13:00–15:00

Kickoff
Changjin Kim, Seunghun Paik, Chanwoo Hwang · Natural Building 702

Jul 15 · 13:00–15:00

Certifiable FR & PAD — I
Hyeonmin Jang, Ingeun Yun · Natural Building 702

Jul 22 · 13:00–15:00

Presentation Attack Detection (PAD) — I
Insoo Kim · Natural Building 701

Jul 29 · 13:00–15:00

Neural Architecture Search (NAS) — I
Minsu Kim, Seunghun Paik, Chanwoo Hwang · Natural Building 206

Aug 5 · 13:00–15:00

Certifiable FR & PAD — II
Pureum Lee, Hyeonmin Jang · Natural Building 702

Aug 12 · 13:00–15:00

Presentation Attack Detection (PAD) — II
Insoo Kim, Ingeun Yun · Natural Building 702

Aug 19 · 13:00–15:00

Neural Architecture Search (NAS) — II
Hyeonmin Jang, Shinwoong Kwak, Insoo Kim · Natural Building 702

2026 · Spring / Summer Seminar

12 sessions

Apr 24 · 10:00–12:00 Slides ↗

Deep Neural Cryptography
Seunghun Paik · Natural Building 702

May 8 · 10:00–12:00 Slides ↗

Towards Deep Conversational Recommendations
Changjin Kim · Natural Building 702

May 15 · 10:00–12:00 Slides ↗

Denoising Diffusion Implicit Models
Minsu Kim · Natural Building 702

May 22 · 10:00–12:00 Slides ↗

Concept-based Adversarial Attack: a Probabilistic Perspective
Chanwoo Hwang · Natural Building 702

Jun 5 · 10:00–12:00 Slides ↗

PRAG: End-to-End Privacy-Preserving Retrieval-Augmented Generation
Hyunjung Son · Online (Zoom)

Jun 19 · 10:00–12:00 Slides ↗

Detecting Generated Images by Fitting Natural Image Distributions
Insoo Kim · Natural Building 702

Jul 10 · 13:00–15:00 Slides ↗

SANNS: Scaling Up Secure Approximate k-Nearest Neighbors Search
Yunki Kim · Natural Building 702

Jul 24 · 13:00–15:00 Slides ↗

Cryptanalytic Extraction of Neural Network Models
Seunghun Paik · Natural Building 206

Jul 31 · 13:00–15:00 Slides ↗

DINOv2: Learning Robust Visual Features without Supervision
Changjin Kim · Natural Building 702

Aug 7 · 13:00–15:00 Slides ↗

Solving Linear Equations Modulo Divisors: On Factoring Given Any Bits
Minsu Kim · Natural Building 702

Aug 14 · 13:00–15:00 Slides ↗

Subliminal Learning: Language models transmit behavioral traits via hidden signals in data
Chanwoo Hwang · Natural Building 702

Aug 21 · 13:00–15:00 TBA

Is the Hard-Label Cryptanalytic Model Extraction Really Polynomial?
Hyunjung Son · Natural Building 702

2026 · Spring · Probabilistic ML Study Group

13 sessions

Textbook: Probabilistic Machine Learning: An Introduction — Kevin P. Murphy · reading the Introduction chapters in order.

May 7 · 17:30–19:30 Slides ↗

Linear Algebra — I (prerequisite)
Minsu Kim · Natural Building 742

May 14 · 17:30–19:30 Slides ↗

Linear Algebra — II (prerequisite)
Minsu Kim · Natural Building 742

May 21 · 17:30–19:30 Slides ↗

Ch 2 & 3 · Probability: Univariate & Multivariate Models
Ingeun Yun · Natural Building 702

May 28 · 17:30–19:30 Slides ↗

Ch 4 & 6 · Statistics & Information Theory — Part 1
Insoo Kim · Natural Building 702

Jun 4 · 17:30–19:30 Slides ↗

Ch 4 & 6 · Statistics & Information Theory — Part 2
Insoo Kim · Natural Building 702

Jul 2 · 13:00–15:00 Slides ↗

Ch 9 & 10 · Linear Discriminant Analysis & Logistic Regression
Hyeonmin Jang · Natural Building 702

Jul 7 · 13:00–15:00 Slides ↗

Ch 11 · Linear Regression
Shinwoong Kwak · Natural Building 702

Jul 9 · 13:00–15:00 Slides ↗

Ch 13 · Neural Networks for Tabular Data
Ingeun Yun · Natural Building 702

Jul 14 · 13:00–15:00 Slides ↗

Ch 14 · Neural Networks for Images
Insoo Kim · Natural Building 702

Jul 16 · 13:00–15:00 Slides ↗

Ch 15 · Neural Networks for Sequences
Shinwoong Kwak · Natural Building 702

Jul 21 · 13:00–15:00 Slides ↗

Ch 17 · Kernel Methods
Minsu Kim · Natural Building 702

Jul 23 · 13:00–15:00 Slides ↗

Ch 19 · Learning with Fewer Labeled Examples
Hyeonmin Jang · Natural Building 702

Aug 6 · 13:00–15:00 Slides ↗

Ch 20 & 21 · Dimensionality Reduction & Clustering
Minsu Kim · Natural Building 702

2025 Fall · 2026 Winter Seminar

9 sessions

Oct 28 · 13:00–15:00 Slides ↗

Fuzzy Private Set Intersection from VOLE
Yunki Kim · Natural Building 702

Nov 4 · 13:00–15:00 Slides ↗

Non-Interactive Multiplication and More
Seunghun Paik · Natural Building 702

Nov 11 · 13:00–15:00 Slides ↗

ICCV 2025 (Conference Review)
Changjin Kim · Natural Building 702

Dec 23 · 15:00–17:00 Slides ↗

NeurIPS 2025 (Conference Review)
Minsu Kim · Natural Building 702

Dec 30 · 15:00–17:00 Slides ↗

Introduction to Text-to-Image Models
Chanwoo Hwang · Natural Building 746

Jan 20 · 15:00–17:00 Slides ↗

Implicit Bias of SGD in L2-regularized Linear DNNs: One-way Jumps from High to Low Rank
Dongsoo Kim · Natural Building B119

Jan 27 · 13:00–15:00 Slides ↗

Mamba: Linear-Time Sequence Modeling with Selective State Spaces
Hyunjung Son · Natural Building 702

Feb 3 · 13:00–15:00 Slides ↗

Back to Basics: Let Denoising Generative Models Denoise
Insoo Kim · Natural Building 702

Feb 10 · 13:00–15:00 Slides ↗

Subspace Collision: An Efficient & Accurate Framework for High-dimensional Approximate Nearest Neighbor Search
Yunki Kim · Natural Building 701

2026 Winter · Special Topic: Vision Language Models

6 sessions

Jan 9 · 15:00–17:00 Slides ↗

Introduction to (Large) Language Models
Seunghun Paik · Natural Building 702

Jan 16 · 15:00–17:00 Slides ↗

Learning Transferable Visual Models from Natural Language Supervision (CLIP)
Changjin Kim · Natural Building B119

Jan 23 · 15:00–17:00 Slides ↗

CLIP Variants
Minsu Kim · Natural Building B119

Jan 30 · 15:00–17:00 Slides ↗

Mind the Gap: About Modality Gap
Chanwoo Hwang · Natural Building 702

Feb 13 · 15:00–17:00 Slides ↗

Attack Methods for CLIP and Vision–Language Pre-trained Models
Dongsoo Kim · Natural Building 702

Feb 20 · 15:00–17:00 Slides ↗

BLIP, BLIP2, and Flamingo
Seunghun Paik · Natural Building 702

Contact

For any inquiries, you can reach us via email: jaehongseo@hanyang.ac.kr