arXiv:2506.01511cs.CV2025-06NeurIPS被引 3

让扩散模型对齐攻击者偏好,提升对抗样本攻击效果与视觉一致性。

Enhancing Diffusion-based Unrestricted Adversarial Attacks via Adversary Preferences Alignment

  • 分两阶段优化:先保视觉质量,再强化攻击效果。
  • 在ImageNet上攻击成功率提升12.3%,且图像质量更高。
  • 适合研究对抗攻击与生成模型对齐的学者。

扩散模型中的偏好对齐通常聚焦于良性人类偏好(如审美)。本文提出新视角:将无限制对抗样本生成视为与攻击者偏好对齐的问题。与良性对齐不同,攻击对齐涉及视觉一致性和攻击有效性两个冲突目标,常导致优化不稳定和奖励劫持(如降低图像质量以提升攻击成功率)。为此,我们提出APA(Adversary Preferences Alignment),一个两阶段框架,通过可微奖励解耦冲突偏好。第一阶段,使用基于规则的相似性奖励微调LoRA以提升视觉一致性;第二阶段,根据替代分类器反馈,更新图像隐变量或提示嵌入,由轨迹级与步骤级奖励引导。为增强黑盒迁移性,进一步引入扩散增强策略。实验表明,APA在保持高视觉一致性的同时显著提升攻击迁移性,启发从对齐视角研究对抗攻击。代码将在https://github.com/deep-kaixun/APA发布。

原文摘要 · Abstract (English)

Preference alignment in diffusion models has primarily focused on benign human preferences (e.g., aesthetic). In this paper, we propose a novel perspective: framing unrestricted adversarial example generation as a problem of aligning with adversary preferences. Unlike benign alignment, adversarial alignment involves two inherently conflicting preferences: visual consistency and attack effectiveness, which often lead to unstable optimization and reward hacking (e.g., reducing visual quality to improve attack success). To address this, we propose APA (Adversary Preferences Alignment), a two-stage framework that decouples conflicting preferences and optimizes each with differentiable rewards. In the first stage, APA fine-tunes LoRA to improve visual consistency using rule-based similarity reward. In the second stage, APA updates either the image latent or prompt embedding based on feedback from a substitute classifier, guided by trajectory-level and step-wise rewards. To enhance black-box transferability, we further incorporate a diffusion augmentation strategy. Experiments demonstrate that APA achieves significantly better attack transferability while maintaining high visual consistency, inspiring further research to approach adversarial attacks from an alignment perspective. Code will be available at https://github.com/deep-kaixun/APA.

对抗攻击扩散模型偏好对齐生成安全

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