Haonan Shi

I am a fourth-year Ph.D. candidate at Case Western Reserve University, advised by Prof. An Wang and co-advised by Dr. Tu Ouyang. Prior to this, I received my bachelor's degree from South China University of Technology, where I conducted research on privacy under the supervision of Prof. Hongyun Xu.
My research focuses on Large Language Model Safety, Agent Safety and Machine Learning Privacy. I am broadly interested in developing methods that make LLM/AI systems safer and more privacy-preserving as they are adapted and deployed in real-world settings.
I am passionate about applying my research to real-world problems and open to internship opportunities and research collaborations.

Email: haonan.shi3[AT]case.edu (please replace "[AT]" by "@")

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News
  • 05/15/2026: “Few Tokens, Big Leverage: Preserving Safety Alignment by Constraining Safety Tokens during Fine-tuning” was accepted to KDD 2026.
  • 11/14/2025: Our AAAI 2026 paper(EASE) was selected as an ORAL presentation.
  • 11/07/2025: “EASE: Practical and Efficient Safety Alignment for Small Language Models” was accepted to AAAI 2026.
  • 06/19/2025: I was honored to receive a Stipend Award from PETS 2025.
  • 05/01/2025: “Unveiling Client Privacy Leakage from Public Dataset Usage in Federated Distillation” was accepted to PoPETs 2025.
  • 03/06/2025: “Navigating the Designs of Privacy-Preserving Fine-tuning for Large Language Models” was also presented at the ICLR 2025 FM-Wild Workshop.
  • 01/20/2025: “Navigating the Designs of Privacy-Preserving Fine-tuning for Large Language Models” was accepted to WWW 2025.
  • 04/05/2024: “Learning-Based Difficulty Calibration for Enhanced Membership Inference Attacks” was accepted to EuroS&P 2024.
Publications
2026
PACT Few Tokens, Big Leverage: Preserving Safety Alignment by Constraining Safety Tokens during Fine-tuning
Guoli Wang*, Haonan Shi*, Tu Ouyang, An Wang
KDD 2026
* indicates equal contribution

We propose PACT, a token-level constrained fine-tuning framework that preserves safety alignment of large language models by regularizing safety-critical tokens while allowing other general tokens to adapt to downstream tasks.

EASE EASE: Practical and Efficient Safety Alignment for Small Language Models
Haonan Shi, Guoli Wang, Tu Ouyang, An Wang
AAAI 2026(oral)

We propose EASE, a practical safety alignment post training framework for small language models that selectively activates safety reasoning for adversarial jailbreak queries while preserving efficiency for benign interactions.

2025
GuardedTuning Navigating the Designs of Privacy-Preserving Fine-tuning for Large Language Models
Haonan Shi, Tu Ouyang, An Wang
WWW 2025

We propose GuardedTuning, a set of privacy-preserving fine-tuning designs that navigate trade-offs among model utility, privacy guarantees, and tuning costs for large language models.

PDA-FD Privacy Leakage Unveiling Client Privacy Leakage from Public Dataset Usage in Federated Distillation
Haonan Shi, Tu Ouyang, An Wang
PoPETs 2025

We reveal privacy risks in public dataset-assisted federated distillation and introduce attacks that infer clients' label distributions and membership information from their predictions on public datasets.

2024
LDC-MIA Learning-Based Difficulty Calibration for Enhanced Membership Inference Attacks
Haonan Shi, Tu Ouyang, An Wang
EuroS&P 2024

We propose LDC-MIA, a learning-based difficulty calibration method that improves membership inference attacks at low false positive rates while maintaining practical attack costs.

2023
KPDP A Trajectory K-Anonymity Model Based on Point Density and Partition
Wanshu Yu*, Haonan Shi*, Hongyun Xu
arXiv 2023
* indicates equal contribution

We propose KPDP, a trajectory k-anonymity model based on point density and partition, to protect trajectory datasets against re-identification attacks while reducing data utility loss.

Industrial Experience
TikTok
Machine Learning Engineer Intern @ Privacy and Data Protection Office
San Jose, CA, USA
2026.04 - 2026.07
TikTok
Machine Learning Engineer Intern @ Privacy and Data Protection Office
San Jose, CA, USA
2026.01 - 2026.04
Education
Case Western Reserve University
Ph.D. in Computer Science
Advisor: Prof. An Wang
Co-Advisor: Dr. Tu Ouyang
Cleveland, OH, USA
2023.09 - present
Case Western Reserve University
Master in Computer Science
Advisor: Prof. An Wang
Co-Advisor: Dr. Tu Ouyang
Cleveland, OH, USA
2022.09 - 2023.05
South China University of Technology
Bachelor of Engineering, Minor in Computer Science
Guangzhou, China
2018.09 - 2022.06
Service
  • Journal Reviewer: Pattern Recognition(2026)
  • Conference Reviewer: KDD(2026), ICLR FM-Wild(2026), ICLR FM4Sci(2026)
Miscellaneous

Outside of research, I love to spend time with Yazai, Meituo, and Tuotuo, who keep my life warm and lively.

Yazai and Meituo
Yazai & Meituo
Tuotuo
Tuotuo

Hello from everywhere:)