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Auteurs principaux: Song, Dinghong, Xu, Zhiwei, Wan, Hai, Zhao, Xibin, Su, Pengfei, Li, Dong
Format: Preprint
Publié: 2026
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Accès en ligne:https://arxiv.org/abs/2601.02680
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author Song, Dinghong
Xu, Zhiwei
Wan, Hai
Zhao, Xibin
Su, Pengfei
Li, Dong
author_facet Song, Dinghong
Xu, Zhiwei
Wan, Hai
Zhao, Xibin
Su, Pengfei
Li, Dong
contents Model quantization is critical for deploying large language models (LLMs) on resource-constrained hardware, yet recent work has revealed severe security risks that benign LLMs in full precision may exhibit malicious behaviors after quantization. In this paper, we propose Adversarial Contrastive Learning (ACL), a novel gradient-based quantization attack that achieves superior attack effectiveness by explicitly maximizing the gap between benign and harmful responses probabilities. ACL formulates the attack objective as a triplet-based contrastive loss, and integrates it with a projected gradient descent two-stage distributed fine-tuning strategy to ensure stable and efficient optimization. Extensive experiments demonstrate ACL's remarkable effectiveness, achieving attack success rates of 86.00% for over-refusal, 97.69% for jailbreak, and 92.40% for advertisement injection, substantially outperforming state-of-the-art methods by up to 44.67%, 18.84%, and 50.80%, respectively.
format Preprint
id arxiv_https___arxiv_org_abs_2601_02680
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle Adversarial Contrastive Learning for LLM Quantization Attacks
Song, Dinghong
Xu, Zhiwei
Wan, Hai
Zhao, Xibin
Su, Pengfei
Li, Dong
Cryptography and Security
Machine Learning
Model quantization is critical for deploying large language models (LLMs) on resource-constrained hardware, yet recent work has revealed severe security risks that benign LLMs in full precision may exhibit malicious behaviors after quantization. In this paper, we propose Adversarial Contrastive Learning (ACL), a novel gradient-based quantization attack that achieves superior attack effectiveness by explicitly maximizing the gap between benign and harmful responses probabilities. ACL formulates the attack objective as a triplet-based contrastive loss, and integrates it with a projected gradient descent two-stage distributed fine-tuning strategy to ensure stable and efficient optimization. Extensive experiments demonstrate ACL's remarkable effectiveness, achieving attack success rates of 86.00% for over-refusal, 97.69% for jailbreak, and 92.40% for advertisement injection, substantially outperforming state-of-the-art methods by up to 44.67%, 18.84%, and 50.80%, respectively.
title Adversarial Contrastive Learning for LLM Quantization Attacks
topic Cryptography and Security
Machine Learning
url https://arxiv.org/abs/2601.02680