Education
  • CISPA Helmholtz Center for Information Security
    CISPA Helmholtz Center for Information Security
    2021.02-2023.10
    Ph.D. in Computer Science, CISPA Helmholtz Center for Information Security. Supervised by Dr. Yang Zhang.
  • Shandong University
    Shandong University
    2017.09-2020.06
    Master in Computer Science, Shandong University. Supervised by Prof. Shanqing Guo.
  • Shandong University
    Shandong University
    2013.09-2017.06
    Bachelor in Computer Science, Shandong University. Supervised by Prof. Shanqing Guo.
  • Experience
  • Shandong University
    Shandong University
    2025.01-current
    Professor at School of Cyber Science and Technology, Shandong University.
  • CISPA Helmholtz Center for Information Security
    CISPA Helmholtz Center for Information Security
    2023.11-2024.12
    Postdoc at CISPA Helmholtz Center for Information Security. Supervised by Dr. Yang Zhang.
  • Bell Lab
    Bell Lab
    2022.07-2022.10
    Research Intern at Bell Lab.
  • About Me

    I am a professor at School of Cyber Science and Technology, Shandong University. Previously, I was a postdoc at CISPA Helmholtz Center for Information Security, supervised by Dr. Yang Zhang. In Oct 2023, I obtained my Ph.D. from CISPA Helmholtz Center for Information Security, supervised by Dr. Yang Zhang. I received my bachelor (2017) and master (2020) degrees from Shandong University, supervised by Prof. Shanqing Guo.

    Research keywords include: Machine learning, Security, Privacy, Safety and so on.

    I am looking for motivated PhD/master students (26 Fall) and research assistants to join my group. If you are interested, please write me an email ([email protected]).
    Research Interests

    My research focuses on Trustworthy Machine Learning, with an emphasis on identifying and mitigating vulnerabilities in AI systems. I investigate privacy attacks (e.g., membership and attribute inference), security threats (e.g., backdoors and data poisoning), and develop technical defenses against unethical AI deployments.

    News
    2025
    One paper “VidLeaks: Membership Inference Attacks Against Text-to-Video Models” got accepted in USENIX Security 2026!
    Dec
    One paper “ErrorTrace: A Black-Box Traceability Mechanism Based on Model Family Error Space” got accepted in NeurIPS 2025 Spotlight!
    Sep
    I’ll serve as the AC of ACL 2026!
    Aug
    One paper “DCMI: A Differential Calibration Membership Inference Attack Against Retrieval-Augmented Generation” got accepted in CCS 2025!
    Aug
    I’ll join the PC of USENIX Security 2026!
    Jul
    One paper “Fuzz-Testing Meets LLM-Based Agents: An Automated and Efficient Framework for Jailbreaking Text-To-Image Generation Models” got accepted in IEEE S&P 2025!
    Mar
    One paper “Membership Inference Attacks Against Vision-Language Models” got accepted in USENIX Security 2025!
    Jan
    One paper “Enhanced Label-Only Membership Inference Attacks with Fewer Queries” got accepted in USENIX Security 2025!
    Jan
    I’ll join the PC of KDD 2025!
    Jan
    I joined Shandong University as a professfor!
    Jan
    Research Highlights
    * Equal contribution, Corresponding author
    Fuzz-Testing Meets LLM-Based Agents: An Automated and Efficient Framework for Jailbreaking Text-To-Image Generation Models
    Fuzz-Testing Meets LLM-Based Agents: An Automated and Efficient Framework for Jailbreaking Text-To-Image Generation Models

    Yingkai Dong, Xiangtao Meng, Ning Yu, Zheng Li, Shanqing Guo

    IEEE S&P 2025

    Text-to-image (T2I) generative models have revolutionized content creation by transforming textual descriptions into high-quality images. However, these models are vulnerable to jailbreaking attacks, where carefully crafted prompts bypass safety mechanisms to produce unsafe content. While researchers have developed various jailbreak attacks to expose this risk, these methods face significant limitations, including impractical access requirements, easily detectable unnatural prompts, restricted search spaces, and high query demands on the target system. ...

    Fuzz-Testing Meets LLM-Based Agents: An Automated and Efficient Framework for Jailbreaking Text-To-Image Generation Models

    Yingkai Dong, Xiangtao Meng, Ning Yu, Zheng Li, Shanqing Guo

    IEEE S&P 2025

    Text-to-image (T2I) generative models have revolutionized content creation by transforming textual descriptions into high-quality images. However, these models are vulnerable to jailbreaking attacks, where carefully crafted prompts bypass safety mechanisms to produce unsafe content. While researchers have developed various jailbreak attacks to expose this risk, these methods face significant limitations, including impractical access requirements, easily detectable unnatural prompts, restricted search spaces, and high query demands on the target system. ...

    Membership Inference Attacks Against In-Context Learning
    Membership Inference Attacks Against In-Context Learning

    Rui Wen, Zheng Li, Michael Backes, Yang Zhang

    CCS 2024

    Adapting Large Language Models (LLMs) to specific tasks introduces concerns about computational efficiency, prompting an exploration of efficient methods such as In-Context Learning (ICL). However, the vulnerability of ICL to privacy attacks under realistic assumptions remains largely unexplored. In this work, we present the first membership inference attack tailored for ICL, relying solely on generated texts without their associated probabilities. We propose four attack strategies tailored to various constrained scenarios and conduct extensive experiments on four popular large language models. ...

    Membership Inference Attacks Against In-Context Learning

    Rui Wen, Zheng Li, Michael Backes, Yang Zhang

    CCS 2024

    Adapting Large Language Models (LLMs) to specific tasks introduces concerns about computational efficiency, prompting an exploration of efficient methods such as In-Context Learning (ICL). However, the vulnerability of ICL to privacy attacks under realistic assumptions remains largely unexplored. In this work, we present the first membership inference attack tailored for ICL, relying solely on generated texts without their associated probabilities. We propose four attack strategies tailored to various constrained scenarios and conduct extensive experiments on four popular large language models. ...

    Auditing Membership Leakages of Multi-Exit Networks
    Auditing Membership Leakages of Multi-Exit Networks

    Zheng Li, Yiyong Liu, Xinlei He, Ning Yu, Michael Backes, Yang Zhang

    CCS 2022

    Relying on the truth that not all inputs require the same level of computational cost to produce reliable predictions, multi-exit networks are gaining attention as a prominent approach for pushing the limits of efficient deployment. Multi-exit networks endow a backbone model with early exits, allowing predictions at intermediate layers of the model and thus saving computation time and energy. However, various current designs of multi-exit networks are only considered to achieve the best trade-off between resource usage efficiency and prediction accuracy, the privacy risks stemming from them have never been explored. This prompts the need for a comprehensive investigation of privacy risks in multi-exit networks. ...

    Auditing Membership Leakages of Multi-Exit Networks

    Zheng Li, Yiyong Liu, Xinlei He, Ning Yu, Michael Backes, Yang Zhang

    CCS 2022

    Relying on the truth that not all inputs require the same level of computational cost to produce reliable predictions, multi-exit networks are gaining attention as a prominent approach for pushing the limits of efficient deployment. Multi-exit networks endow a backbone model with early exits, allowing predictions at intermediate layers of the model and thus saving computation time and energy. However, various current designs of multi-exit networks are only considered to achieve the best trade-off between resource usage efficiency and prediction accuracy, the privacy risks stemming from them have never been explored. This prompts the need for a comprehensive investigation of privacy risks in multi-exit networks. ...

    Membership Leakage in Label-Only Exposures
    Membership Leakage in Label-Only Exposures

    Zheng Li, Yang Zhang

    CCS 2021

    Machine learning (ML) has been widely adopted in various privacy-critical applications, e.g., face recognition and medical image analysis. However, recent research has shown that ML models are vulnerable to attacks against their training data. Membership inference is one major attack in this domain: Given a data sample and model, an adversary aims to determine whether the sample is part of the model's training set. Existing membership inference attacks leverage the confidence scores returned by the model as their inputs (score-based attacks). However, these attacks can be easily mitigated if the model only exposes the predicted label, i.e., the final model decision. ...

    Membership Leakage in Label-Only Exposures

    Zheng Li, Yang Zhang

    CCS 2021

    Machine learning (ML) has been widely adopted in various privacy-critical applications, e.g., face recognition and medical image analysis. However, recent research has shown that ML models are vulnerable to attacks against their training data. Membership inference is one major attack in this domain: Given a data sample and model, an adversary aims to determine whether the sample is part of the model's training set. Existing membership inference attacks leverage the confidence scores returned by the model as their inputs (score-based attacks). However, these attacks can be easily mitigated if the model only exposes the predicted label, i.e., the final model decision. ...

    All Research