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Michael Backes

27 accepted papers

2026

Benchmarking Empirical Privacy Protection for Adaptations of Large Language Models

ICLR 2026oral

Recent work has applied differential privacy (DP) to adapt large language models (LLMs) for sensitive applications, offering theoretical guarantees. However, its practical effectiveness remains unclear, partly due to LLM pretraining, where overlaps and interdependencies with adaptation data can unde…

Cited by 0SourceScholar
2026

Sparse Models, Sparse Safety: Unsafe Routes in Mixture-of-Experts LLMs

ICML 2026poster

By introducing routers to selectively activate experts in Transformer layers, the mixture-of-experts (MoE) architecture significantly reduces computational costs in large language models (LLMs) while maintaining competitive performance, especially for models with massive parameters. However, prior w…

Cited by 0SourceScholar
2026

TrustGen: A Platform of Dynamic Benchmarking on the Trustworthiness of Generative Foundation Models

ICLR 2026poster

Generative foundation models (GenFMs), such as large language models and text-to-image systems, have demonstrated remarkable capabilities in various downstream applications. As they are increasingly deployed in high-stakes applications, assessing their trustworthiness has become both a critical nece…

Cited by 0SourceScholar
2026

When Understanding Becomes a Risk: Authenticity and Safety Risks in the Emerging Image Generation Paradigm

CVPR 2026

Recently, multimodal large language models (MLLMs) have emerged as a unified paradigm for language and image generation. Compared with diffusion models, MLLMs possess a much stronger capability for semantic understanding, enabling them to process more complex textual inputs and comprehend richer con

Cited by 0SourceScholar
2025

Adjacent Words, Divergent Intents: Jailbreaking Large Language Models via Task Concurrency

NeurIPS 2025poster

Despite their superior performance on a wide range of domains, large language models (LLMs) remain vulnerable to misuse for generating harmful content, a risk that has been further amplified by various jailbreak attacks. Existing jailbreak attacks mainly follow sequential logic, where LLMs understan…

Cited by 0SourcecodeScholar
2025

Are We in the AI-Generated Text World Already? Quantifying and Monitoring AIGT on Social Media

ACL 2025long

Social media platforms are experiencing a growing presence of AI-Generated Texts (AIGTs). However, the misuse of AIGTs could have profound implications for public opinion, such as spreading misinformation and manipulating narratives. Despite its importance, it remains unclear how prevalent AIGTs are…

2025

Breaking Agents: Compromising Autonomous LLM Agents Through Malfunction Amplification

EMNLP 2025

Recently, autonomous agents built on large language models (LLMs) have experienced significant development and are being deployed in real-world applications. Through the usage of tools, these systems can perform actions in the real world. Given the agents’ practical applications and ability to execu

2025

Captured by Captions: On Memorization and its Mitigation in CLIP Models

ICLR 2025poster

Multi-modal models, such as CLIP, have demonstrated strong performance in aligning visual and textual representations, excelling in tasks like image retrieval and zero-shot classification. Despite this success, the mechanisms by which these models utilize training data, particularly the role of memo…

Cited by 0SourcePDFScholar
2025

Efficient and Privacy-Preserving Soft Prompt Transfer for LLMs

ICML 2025poster

Prompting has become a dominant paradigm for adapting large language models (LLMs). While discrete (textual) prompts are widely used for their interpretability, soft (parameter) prompts have recently gained traction in APIs. This is because they can encode information from more training samples whil…

Cited by 0SourcePDFScholar
2025

Finding and Reactivating Post-Trained LLMs' Hidden Safety Mechanisms

NeurIPS 2025poster

Despite the impressive performance of general-purpose large language models (LLMs), they often require fine-tuning or post-training to excel at specific tasks. For instance, large reasoning models (LRMs), such as the DeepSeek-R1 series, demonstrate strong reasoning capabilities after post-train…

Cited by 0SourceScholar
2025

Hate in Plain Sight: On the Risks of Moderating AI-Generated Hateful Illusions

ICCV 2025poster

Recent advances in text-to-image diffusion models have enabled the creation of a new form of digital art: optical illusions---visual tricks that create different perceptions of reality. However, adversaries may misuse such techniques to generate hateful illusions, which embed specific hate messages…

Cited by 0SourcePDFScholar
2025

JailbreakRadar: Comprehensive Assessment of Jailbreak Attacks Against LLMs

ACL 2025long

Jailbreak attacks aim to bypass the LLMs’ safeguards. While researchers have proposed different jailbreak attacks in depth, they have done so in isolation—either with unaligned settings or comparing a limited range of methods. To fill this gap, we present a large-scale evaluation of various jailbrea…

2025

Provably Cost-Sensitive Adversarial Defense via Randomized Smoothing

ICML 2025poster

As machine learning models are deployed in critical applications, robustness against adversarial perturbations is crucial. While numerous defensive algorithms have been proposed to counter such attacks, they typically assume that all adversarial transformations are equally important, an assumption t…

2025

SaLoRA: Safety-Alignment Preserved Low-Rank Adaptation

ICLR 2025poster

As advancements in large language models (LLMs) continue and the demand for personalized models increases, parameter-efficient fine-tuning (PEFT) methods (e.g., LoRA) become essential due to their efficiency in reducing computation costs. However, recent studies have raised alarming concerns that Lo…

Cited by 3SourcePDFScholar
2025

When GPT Spills the Tea: Comprehensive Assessment of Knowledge File Leakage in GPTs

ACL 2025long

Knowledge files have been widely used in large language model (LLM)-powered agents, such as GPTs, to improve response quality. However, concerns over the potential leakage of knowledge files have grown significantly. Existing studies demonstrate that adversarial prompts can induce GPTs to leak knowl…

Cited by 0SourcePDFScholar
2024

Composite Backdoor Attacks Against Large Language Models

NAACL 2024findings

Large language models (LLMs) have demonstrated superior performance compared to previous methods on various tasks, and often serve as the foundation models for many researches and services. However, the untrustworthy third-party LLMs may covertly introduce vulnerabilities for downstream tasks. In th…

2024

Detection and Attribution of Models Trained on Generated Data

ICASSP 2024accepted

Generative Adversarial Networks (GANs) have become widely used in model training, as they can improve performance and/or protect sensitive information by generating data. However, this also raises potential risks, as malicious GANs may compromise or sabotage models by poisoning their training data.…

Cited by 0SourceScholar
2024

Memorization in Self-Supervised Learning Improves Downstream Generalization

ICLR 2024poster

Self-supervised learning (SSL) has recently received significant attention due to its ability to train high-performance encoders purely on unlabeled data---often scraped from the internet. This data can still be sensitive and empirical evidence suggests that SSL encoders memorize private information…

2024

Open LLMs are Necessary for Current Private Adaptations and Outperform their Closed Alternatives

NeurIPS 2024poster

While open Large Language Models (LLMs) have made significant progress, they still fall short of matching the performance of their closed, proprietary counterparts, making the latter attractive even for the use on highly *private* data. Recently, various new methods have been proposed to adapt clos…

Cited by 2SourcePDFScholar
2024

Position: TrustLLM: Trustworthiness in Large Language Models

ICML 2024poster

Large language models (LLMs) have gained considerable attention for their excellent natural language processing capabilities. Nonetheless, these LLMs present many challenges, particularly in the realm of trustworthiness. This paper introduces TrustLLM, a comprehensive study of trustworthiness in LLM…

Cited by 95SourcePDFScholar
2024

Reconstruct Your Previous Conversations! Comprehensively Investigating Privacy Leakage Risks in Conversations with GPT Models

EMNLP 2024main

Significant advancements have recently been made in large language models, represented by GPT models.Users frequently have multi-round private conversations with cloud-hosted GPT models for task optimization.Yet, this operational paradigm introduces additional attack surfaces, particularly in custom…

2024

The Death and Life of Great Prompts: Analyzing the Evolution of LLM Prompts from the Structural Perspective

EMNLP 2024main

Effective utilization of large language models (LLMs), such as ChatGPT, relies on the quality of input prompts. This paper explores prompt engineering, specifically focusing on the disparity between experimentally designed prompts and real-world “in-the-wild” prompts. We analyze 10,538 in-the-wild p…

Cited by 0SourcePDFScholar
2023

Can't Steal? Cont-Steal! Contrastive Stealing Attacks Against Image Encoders

CVPR 2023poster

Self-supervised representation learning techniques have been developing rapidly to make full use of unlabeled images. They encode images into rich features that are oblivious to downstream tasks. Behind their revolutionary representation power, the requirements for dedicated model designs and a mass…

2023

Data Poisoning Attacks Against Multimodal Encoders

ICML 2023poster

Recently, the newly emerged multimodal models, which leverage both visual and linguistic modalities to train powerful encoders, have gained increasing attention. However, learning from a large-scale unlabeled dataset also exposes the model to the risk of potential poisoning attacks, whereby the adve…

2023

Is Adversarial Training Really a Silver Bullet for Mitigating Data Poisoning?

ICLR 2023top-25%

Indiscriminate data poisoning can decrease the clean test accuracy of a deep learning model by slightly perturbing its training samples. There is a consensus that such poisons can hardly harm adversarially-trained (AT) models when the adversarial training budget is no less than the poison budget, i.…