论文标题
基于梯度的对抗攻击的扰动分析
Perturbation Analysis of Gradient-based Adversarial Attacks
论文作者
论文摘要
在发现对抗性示例及其对深度学习模型的不利影响之后,许多研究着重于寻找更多样化的方法来生成这些精心制作的样本。尽管在文献中详细讨论了针对防御机制的对抗性示例产生方法的有效性的经验结果,但在很大程度上缺乏对这些对抗性攻击的理论特性的深入研究和这些对抗性攻击的扰动有效性。在本文中,我们研究了三种流行的对抗性示例的流行方法的目标功能:L-BFGS攻击,迭代快速梯度标志攻击以及Carlini&Wagner的攻击(CW)。具体而言,我们对上述攻击基础的损失函数进行了比较和正式分析,同时在Imagenet数据集上提出了大规模的实验结果。该分析揭示了(1)更快的优化速度以及横向渗透损失的约束优化空间,(2)使用跨凝性损失对优化精度和优化空间的签名的有害影响,以及(3)在敌对性背景下逻辑损失的慢速优化速度。我们的实验表明,迭代快速梯度攻击被认为是生成对抗性示例的快速攻击,这是在相同扰动的情况下创建对抗性示例所需的迭代次数的最糟糕的攻击。此外,我们的实验表明,CW的潜在损失函数比其他损失功能要慢得多。最后,我们分析了神经网络如何识别所考虑的攻击产生的对抗性扰动,从而重新审视了ImageNet上对抗性训练的想法。
After the discovery of adversarial examples and their adverse effects on deep learning models, many studies focused on finding more diverse methods to generate these carefully crafted samples. Although empirical results on the effectiveness of adversarial example generation methods against defense mechanisms are discussed in detail in the literature, an in-depth study of the theoretical properties and the perturbation effectiveness of these adversarial attacks has largely been lacking. In this paper, we investigate the objective functions of three popular methods for adversarial example generation: the L-BFGS attack, the Iterative Fast Gradient Sign attack, and Carlini & Wagner's attack (CW). Specifically, we perform a comparative and formal analysis of the loss functions underlying the aforementioned attacks while laying out large-scale experimental results on ImageNet dataset. This analysis exposes (1) the faster optimization speed as well as the constrained optimization space of the cross-entropy loss, (2) the detrimental effects of using the signature of the cross-entropy loss on optimization precision as well as optimization space, and (3) the slow optimization speed of the logit loss in the context of adversariality. Our experiments reveal that the Iterative Fast Gradient Sign attack, which is thought to be fast for generating adversarial examples, is the worst attack in terms of the number of iterations required to create adversarial examples in the setting of equal perturbation. Moreover, our experiments show that the underlying loss function of CW, which is criticized for being substantially slower than other adversarial attacks, is not that much slower than other loss functions. Finally, we analyze how well neural networks can identify adversarial perturbations generated by the attacks under consideration, hereby revisiting the idea of adversarial retraining on ImageNet.