Search Results for author: Wenzhi Chen

Found 11 papers, 7 papers with code

DC-SGD: Differentially Private SGD with Dynamic Clipping through Gradient Norm Distribution Estimation

no code implementations29 Mar 2025 Chengkun Wei, Weixian Li, Chen Gong, Wenzhi Chen

In this paper, we propose Dynamic Clipping DP-SGD (DC-SGD), a framework that leverages differentially private histograms to estimate gradient norm distributions and dynamically adjust the clipping threshold C. Our framework includes two novel mechanisms: DC-SGD-P and DC-SGD-E. DC-SGD-P adjusts the clipping threshold based on a percentile of gradient norms, while DC-SGD-E minimizes the expected squared error of gradients to optimize C. These dynamic adjustments significantly reduce the burden of hyperparameter tuning C. The extensive experiments on various deep learning tasks, including image classification and natural language processing, show that our proposed dynamic algorithms achieve up to 9 times acceleration on hyperparameter tuning than DP-SGD.

Deep Learning Image Classification +2

Dialogue Injection Attack: Jailbreaking LLMs through Context Manipulation

1 code implementation11 Mar 2025 Wenlong Meng, Fan Zhang, Wendao Yao, Zhenyuan Guo, Yuwei Li, Chengkun Wei, Wenzhi Chen

Our experiments show that DIA achieves state-of-the-art attack success rates on recent LLMs, including Llama-3. 1 and GPT-4o.

Be Cautious When Merging Unfamiliar LLMs: A Phishing Model Capable of Stealing Privacy

1 code implementation17 Feb 2025 Zhenyuan Guo, Yi Shi, Wenlong Meng, Chen Gong, Chengkun Wei, Wenzhi Chen

Specifically, we propose PhiMM, a privacy attack approach that trains a phishing model capable of stealing privacy using a crafted privacy phishing instruction dataset.

Exploring ChatGPT's Capabilities on Vulnerability Management

1 code implementation11 Nov 2023 Peiyu Liu, Junming Liu, Lirong Fu, Kangjie Lu, Yifan Xia, Xuhong Zhang, Wenzhi Chen, Haiqin Weng, Shouling Ji, Wenhai Wang

Prior works show that ChatGPT has the capabilities of processing foundational code analysis tasks, such as abstract syntax tree generation, which indicates the potential of using ChatGPT to comprehend code syntax and static behaviors.

Management

LMSanitator: Defending Prompt-Tuning Against Task-Agnostic Backdoors

1 code implementation26 Aug 2023 Chengkun Wei, Wenlong Meng, Zhikun Zhang, Min Chen, Minghu Zhao, Wenjing Fang, Lei Wang, Zihui Zhang, Wenzhi Chen

Instead of directly inverting the triggers, LMSanitator aims to invert the predefined attack vectors (pretrained models' output when the input is embedded with triggers) of the task-agnostic backdoors, which achieves much better convergence performance and backdoor detection accuracy.

DPMLBench: Holistic Evaluation of Differentially Private Machine Learning

1 code implementation10 May 2023 Chengkun Wei, Minghu Zhao, Zhikun Zhang, Min Chen, Wenlong Meng, Bo Liu, Yuan Fan, Wenzhi Chen

We also explore some improvements that can maintain model utility and defend against MIAs more effectively.

Image Classification

Diff-ID: An Explainable Identity Difference Quantification Framework for DeepFake Detection

no code implementations30 Mar 2023 Chuer Yu, Xuhong Zhang, Yuxuan Duan, Senbo Yan, Zonghui Wang, Yang Xiang, Shouling Ji, Wenzhi Chen

We then visualize the identity loss between the test and the reference image from the image differences of the aligned pairs, and design a custom metric to quantify the identity loss.

Attribute DeepFake Detection +1

Watch Out for the Confusing Faces: Detecting Face Swapping with the Probability Distribution of Face Identification Models

no code implementations23 Mar 2023 Yuxuan Duan, Xuhong Zhang, Chuer Yu, Zonghui Wang, Shouling Ji, Wenzhi Chen

We reflect this nature with the confusion of a face identification model and measure the confusion with the maximum value of the output probability distribution.

Face Identification Face Swapping

A Robust Scheme for 3D Point Cloud Copy Detection

no code implementations3 Oct 2021 Jiaqi Yang, Xuequan Lu, Wenzhi Chen

In this paper, we focus on a fundamental and practical research problem: judging whether a point cloud is plagiarized or copied to another point cloud in the presence of several manipulations (e. g., similarity transformation, smoothing).

3D geometry Copy Detection

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