arXiv:2412.08394cs.LG2024-12中稿 · TPAMI

用生成模型的潜在空间优化,修复对抗样本并保留真实信息。

Adversarial Purification by Consistency-aware Latent Space Optimization on Data Manifolds

  • 在生成模型的潜在空间中优化,通过感知一致性恢复原始图像。
  • 引入分布对齐约束,确保修复结果保持在真实数据流形内。
  • 适合关注对抗鲁棒性提升与图像质量保护的研究者使用。

深度神经网络易受微小扰动构造的对抗样本影响,导致错误甚至危险预测。对抗净化可通过去除扰动提升模型鲁棒性,但常因扰动不可察觉而过度修正,破坏关键结构与语义信息。本文提出一致性模型驱动的对抗净化方法(CMAP),聚焦于干净数据流形。我们发现训练良好的生成模型所产样本接近干净样本,远离对抗样本。CMAP通过优化预训练一致性模型的潜在向量,生成用于恢复清洁数据的样本:1)在像素与感知空间最小化生成样本与输入样本的差异,实现感知一致性恢复;2)引入潜在分布一致性约束,使生成样本与干净数据分布对齐,确保位于有效数据流形内;3)采用集成策略预测潜在向量一致性,提升预测可靠性。实验表明,在CIFAR-10和ImageNet-100上,CMAP显著增强对强对抗攻击的鲁棒性,同时保持高自然准确率。

原文摘要 · Abstract (English)

Deep neural networks (DNNs) are vulnerable to adversarial samples crafted by adding imperceptible perturbations to clean data, potentially leading to incorrect and dangerous predictions. Adversarial purification has been an effective means to improve DNNs robustness by removing these perturbations before feeding the data into the model. However, it faces significant challenges in preserving key structural and semantic information of data, as the imperceptible nature of adversarial perturbations makes it hard to avoid over-correcting, which can destroy important information and degrade model performance. In this paper, we break away from traditional adversarial purification methods by focusing on the clean data manifold. To this end, we reveal that samples generated by a well-trained generative model are close to clean ones but far from adversarial ones. Leveraging this insight, we propose Consistency Model-based Adversarial Purification (CMAP), which optimizes vectors within the latent space of a pre-trained consistency model to generate samples for restoring clean data. Specifically, 1) we propose a Perceptual consistency restoration mechanism by minimizing the discrepancy between generated samples and input samples in both pixel and perceptual spaces. 2) To maintain the optimized latent vectors within the valid data manifold, we introduce a Latent distribution consistency constraint strategy to align generated samples with the clean data distribution. 3) We also apply a Latent vector consistency prediction scheme via an ensemble approach to enhance prediction reliability. CMAP fundamentally addresses adversarial perturbations at their source, providing a robust purification. Extensive experiments on CIFAR-10 and ImageNet-100 show that our CMAP significantly enhances robustness against strong adversarial attacks while preserving high natural accuracy.

对抗样本生成模型数据流形净化

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