对抗性的鲁棒性已经成为深度学习的核心目标，无论是在理论和实践中。然而，成功的方法来改善对抗的鲁棒性（如逆势训练）在不受干扰的数据上大大伤害了泛化性能。这可能会对对抗性鲁棒性如何影响现实世界系统的影响（即，如果它可以提高未受干扰的数据的准确性），许多人可能选择放弃鲁棒性）。我们提出内插对抗培训，该培训最近雇用了在对抗培训框架内基于插值的基于插值的培训方法。在CiFar -10上，对抗性训练增加了标准测试错误（当没有对手时）从4.43％到12.32％，而我们的内插对抗培训我们保留了对抗性的鲁棒性，同时实现了仅6.45％的标准测试误差。通过我们的技术，强大模型标准误差的相对增加从178.1％降至仅为45.5％。此外，我们提供内插对抗性培训的数学分析，以确认其效率，并在鲁棒性和泛化方面展示其优势。

我们介绍了嘈杂的特征混音（NFM），这是一个廉价但有效的数据增强方法，这些方法结合了基于插值的训练和噪声注入方案。不是用凸面的示例和它们的标签的凸面组合训练，而不是在输入和特征空间中使用对数据点对的噪声扰动凸组合。该方法包括混合和歧管混合作为特殊情况，但它具有额外的优点，包括更好地平滑决策边界并实现改进的模型鲁棒性。我们提供理论要理解这一点以及NFM的隐式正则化效果。与混合和歧管混合相比，我们的理论得到了经验结果的支持，展示了NFM的优势。我们表明，在一系列计算机视觉基准数据集中，使用NFM培训的剩余网络和视觉变压器在清洁数据的预测准确性和鲁棒性之间具有有利的权衡。

We identify a trade-off between robustness and accuracy that serves as a guiding principle in the design of defenses against adversarial examples. Although this problem has been widely studied empirically, much remains unknown concerning the theory underlying this trade-off. In this work, we decompose the prediction error for adversarial examples (robust error) as the sum of the natural (classification) error and boundary error, and provide a differentiable upper bound using the theory of classification-calibrated loss, which is shown to be the tightest possible upper bound uniform over all probability distributions and measurable predictors. Inspired by our theoretical analysis, we also design a new defense method, TRADES, to trade adversarial robustness off against accuracy. Our proposed algorithm performs well experimentally in real-world datasets. The methodology is the foundation of our entry to the NeurIPS 2018 Adversarial Vision Challenge in which we won the 1st place out of ~2,000 submissions, surpassing the runner-up approach by 11.41% in terms of mean 2 perturbation distance.

Recent work has demonstrated that deep neural networks are vulnerable to adversarial examples-inputs that are almost indistinguishable from natural data and yet classified incorrectly by the network. In fact, some of the latest findings suggest that the existence of adversarial attacks may be an inherent weakness of deep learning models. To address this problem, we study the adversarial robustness of neural networks through the lens of robust optimization. This approach provides us with a broad and unifying view on much of the prior work on this topic. Its principled nature also enables us to identify methods for both training and attacking neural networks that are reliable and, in a certain sense, universal. In particular, they specify a concrete security guarantee that would protect against any adversary. These methods let us train networks with significantly improved resistance to a wide range of adversarial attacks. They also suggest the notion of security against a first-order adversary as a natural and broad security guarantee. We believe that robustness against such well-defined classes of adversaries is an important stepping stone towards fully resistant deep learning models. 1

改善深度神经网络（DNN）对抗对抗示例的鲁棒性是安全深度学习的重要而挑战性问题。跨越现有的防御技术，具有预计梯度体面（PGD）的对抗培训是最有效的。对手训练通过最大化分类丢失，通过最大限度地减少从内在最大化生成的逆势示例的丢失来解决\ excepitient {内部最大化}生成侵略性示例的初始最大优化问题。 。因此，衡量内部最大化的衡量标准是如何对对抗性培训至关重要的。在本文中，我们提出了这种标准，即限制优化（FOSC）的一阶静止条件，以定量评估内部最大化中发现的对抗性实例的收敛质量。通过FOSC，我们发现，为了确保更好的稳健性，必须在培训的\ Texit {稍后的阶段}中具有更好的收敛质量的对抗性示例。然而，在早期阶段，高收敛质量的对抗例子不是必需的，甚至可能导致稳健性差。基于这些观察，我们提出了一种\ Texit {动态}培训策略，逐步提高产生的对抗性实例的收敛质量，这显着提高了对抗性培训的鲁棒性。我们的理论和经验结果表明了该方法的有效性。

Adaptive attacks have (rightfully) become the de facto standard for evaluating defenses to adversarial examples. We find, however, that typical adaptive evaluations are incomplete. We demonstrate that thirteen defenses recently published at ICLR, ICML and NeurIPS-and which illustrate a diverse set of defense strategies-can be circumvented despite attempting to perform evaluations using adaptive attacks. While prior evaluation papers focused mainly on the end result-showing that a defense was ineffective-this paper focuses on laying out the methodology and the approach necessary to perform an adaptive attack. Some of our attack strategies are generalizable, but no single strategy would have been sufficient for all defenses. This underlines our key message that adaptive attacks cannot be automated and always require careful and appropriate tuning to a given defense. We hope that these analyses will serve as guidance on how to properly perform adaptive attacks against defenses to adversarial examples, and thus will allow the community to make further progress in building more robust models.

Adversarial examples are perturbed inputs designed to fool machine learning models. Adversarial training injects such examples into training data to increase robustness. To scale this technique to large datasets, perturbations are crafted using fast single-step methods that maximize a linear approximation of the model's loss. We show that this form of adversarial training converges to a degenerate global minimum, wherein small curvature artifacts near the data points obfuscate a linear approximation of the loss. The model thus learns to generate weak perturbations, rather than defend against strong ones. As a result, we find that adversarial training remains vulnerable to black-box attacks, where we transfer perturbations computed on undefended models, as well as to a powerful novel single-step attack that escapes the non-smooth vicinity of the input data via a small random step. We further introduce Ensemble Adversarial Training, a technique that augments training data with perturbations transferred from other models. On ImageNet, Ensemble Adversarial Training yields models with stronger robustness to blackbox attacks. In particular, our most robust model won the first round of the NIPS 2017 competition on Defenses against Adversarial Attacks (Kurakin et al., 2017c). However, subsequent work found that more elaborate black-box attacks could significantly enhance transferability and reduce the accuracy of our models.

Deep neural networks excel at learning the training data, but often provide incorrect and confident predictions when evaluated on slightly different test examples. This includes distribution shifts, outliers, and adversarial examples. To address these issues, we propose Manifold Mixup, a simple regularizer that encourages neural networks to predict less confidently on interpolations of hidden representations. Manifold Mixup leverages semantic interpolations as additional training signal, obtaining neural networks with smoother decision boundaries at multiple levels of representation. As a result, neural networks trained with Manifold Mixup learn class-representations with fewer directions of variance. We prove theory on why this flattening happens under ideal conditions, validate it on practical situations, and connect it to previous works on information theory and generalization. In spite of incurring no significant computation and being implemented in a few lines of code, Manifold Mixup improves strong baselines in supervised learning, robustness to single-step adversarial attacks, and test log-likelihood.

The study on improving the robustness of deep neural networks against adversarial examples grows rapidly in recent years. Among them, adversarial training is the most promising one, which flattens the input loss landscape (loss change with respect to input) via training on adversarially perturbed examples. However, how the widely used weight loss landscape (loss change with respect to weight) performs in adversarial training is rarely explored. In this paper, we investigate the weight loss landscape from a new perspective, and identify a clear correlation between the flatness of weight loss landscape and robust generalization gap. Several well-recognized adversarial training improvements, such as early stopping, designing new objective functions, or leveraging unlabeled data, all implicitly flatten the weight loss landscape. Based on these observations, we propose a simple yet effective Adversarial Weight Perturbation (AWP) to explicitly regularize the flatness of weight loss landscape, forming a double-perturbation mechanism in the adversarial training framework that adversarially perturbs both inputs and weights. Extensive experiments demonstrate that AWP indeed brings flatter weight loss landscape and can be easily incorporated into various existing adversarial training methods to further boost their adversarial robustness.

深度卷积神经网络（CNN）很容易被输入图像的细微，不可察觉的变化所欺骗。为了解决此漏洞，对抗训练会创建扰动模式，并将其包括在培训设置中以鲁棒性化模型。与仅使用阶级有限信息的现有对抗训练方法（例如，使用交叉渗透损失）相反，我们建议利用功能空间中的其他信息来促进更强的对手，这些信息又用于学习强大的模型。具体来说，我们将使用另一类的目标样本的样式和内容信息以及其班级边界信息来创建对抗性扰动。我们以深入监督的方式应用了我们提出的多任务目标，从而提取了多尺度特征知识，以创建最大程度地分开对手。随后，我们提出了一种最大边缘对抗训练方法，该方法可最大程度地减少源图像与其对手之间的距离，并最大程度地提高对手和目标图像之间的距离。与最先进的防御能力相比，我们的对抗训练方法表明了强大的鲁棒性，可以很好地推广到自然发生的损坏和数据分配变化，并保留了清洁示例的模型准确性。

在本讨论文件中，我们调查了有关机器学习模型鲁棒性的最新研究。随着学习算法在数据驱动的控制系统中越来越流行，必须确保它们对数据不确定性的稳健性，以维持可靠的安全至关重要的操作。我们首先回顾了这种鲁棒性的共同形式主义，然后继续讨论训练健壮的机器学习模型的流行和最新技术，以及可证明这种鲁棒性的方法。从强大的机器学习的这种统一中，我们识别并讨论了该地区未来研究的迫切方向。

深度神经网络很容易被称为对抗攻击的小扰动都愚弄。对抗性培训（AT）是一种近似解决了稳健的优化问题，以最大限度地减少最坏情况损失，并且被广泛认为是对这种攻击的最有效的防御。由于产生了强大的对抗性示例的高计算时间，已经提出了单步方法来减少培训时间。然而，这些方法遭受灾难性的过度装备，在训练期间侵犯准确度下降。虽然提出了改进，但它们增加了培训时间和稳健性远非多步骤。我们为FW优化（FW-AT）开发了对抗的对抗培训的理论框架，揭示了损失景观与$ \ ell_2 $失真之间的几何连接。我们分析地表明FW攻击的高变形相当于沿攻击路径的小梯度变化。然后在各种深度神经网络架构上进行实验证明，$ \ ell \ infty $攻击对抗强大的模型实现近乎最大的$ \ ell_2 $失真，而标准网络具有较低的失真。此外，实验表明，灾难性的过度拟合与FW攻击的低变形强烈相关。为了展示我们理论框架的效用，我们开发FW-AT-Adap，这是一种新的逆势训练算法，它使用简单的失真度量来调整攻击步骤的数量，以提高效率而不会影响鲁棒性。 FW-AT-Adapt提供培训时间以单步快速分配方法，并改善了在白色盒子和黑匣子设置中的普发内精度的最小损失和多步PGD之间的差距。

This paper investigates recently proposed approaches for defending against adversarial examples and evaluating adversarial robustness. We motivate adversarial risk as an objective for achieving models robust to worst-case inputs. We then frame commonly used attacks and evaluation metrics as defining a tractable surrogate objective to the true adversarial risk. This suggests that models may optimize this surrogate rather than the true adversarial risk. We formalize this notion as obscurity to an adversary, and develop tools and heuristics for identifying obscured models and designing transparent models. We demonstrate that this is a significant problem in practice by repurposing gradient-free optimization techniques into adversarial attacks, which we use to decrease the accuracy of several recently proposed defenses to near zero. Our hope is that our formulations and results will help researchers to develop more powerful defenses.

It is common practice in deep learning to use overparameterized networks and train for as long as possible; there are numerous studies that show, both theoretically and empirically, that such practices surprisingly do not unduly harm the generalization performance of the classifier. In this paper, we empirically study this phenomenon in the setting of adversarially trained deep networks, which are trained to minimize the loss under worst-case adversarial perturbations. We find that overfitting to the training set does in fact harm robust performance to a very large degree in adversarially robust training across multiple datasets (SVHN, CIFAR-10, CIFAR-100, and ImageNet) and perturbation models ( ∞ and 2 ). Based upon this observed effect, we show that the performance gains of virtually all recent algorithmic improvements upon adversarial training can be matched by simply using early stopping. We also show that effects such as the double descent curve do still occur in adversarially trained models, yet fail to explain the observed overfitting. Finally, we study several classical and modern deep learning remedies for overfitting, including regularization and data augmentation, and find that no approach in isolation improves significantly upon the gains achieved by early stopping. All code for reproducing the experiments as well as pretrained model weights and training logs can be found at https://github.com/ locuslab/robust_overfitting.

尽管机器学习系统的效率和可扩展性，但最近的研究表明，许多分类方法，尤其是深神经网络（DNN），易受对抗的例子;即，仔细制作欺骗训练有素的分类模型的例子，同时无法区分从自然数据到人类。这使得在安全关键区域中应用DNN或相关方法可能不安全。由于这个问题是由Biggio等人确定的。 （2013）和Szegedy等人。（2014年），在这一领域已经完成了很多工作，包括开发攻击方法，以产生对抗的例子和防御技术的构建防范这些例子。本文旨在向统计界介绍这一主题及其最新发展，主要关注对抗性示例的产生和保护。在数值实验中使用的计算代码（在Python和R）公开可用于读者探讨调查的方法。本文希望提交人们将鼓励更多统计学人员在这种重要的令人兴奋的领域的产生和捍卫对抗的例子。

深度神经网络（DNN）容易受到对抗性示例的影响，其中DNN由于含有不可察觉的扰动而被误导为虚假输出。对抗性训练是一种可靠有效的防御方法，可能会大大减少神经网络的脆弱性，并成为强大学习的事实上的标准。尽管许多最近的作品实践了以数据为中心的理念，例如如何生成更好的对抗性示例或使用生成模型来产生额外的培训数据，但我们回顾了模型本身，并从深度特征分布的角度重新审视对抗性的鲁棒性有见地的互补性。在本文中，我们建议分支正交性对抗训练（BORT）获得最先进的性能，仅使用原始数据集用于对抗训练。为了练习我们整合多个正交解决方案空间的设计思想，我们利用一个简单明了的多分支神经网络，可消除对抗性攻击而不会增加推理时间。我们启发提出相应的损耗函数，分支 - 正交丢失，以使多支出模型正交的每个溶液空间。我们分别在CIFAR-10，CIFAR-100和SVHN上评估了我们的方法，分别针对\ ell _ {\ infty}的规范触发尺寸\ epsilon = 8/255。进行了详尽的实验，以表明我们的方法超出了所有最新方法，而无需任何技巧。与所有不使用其他数据进行培训的方法相比，我们的模型在CIFAR-10和CIFAR-100上实现了67.3％和41.5％的鲁棒精度（在最先进的ART上提高了 +7.23％和 +9.07％ ）。我们还使用比我们的训练组胜过比我们的方法的表现要大得多。我们所有的模型和代码均可在https://github.com/huangd1999/bort上在线获得。

几个数据增强方法部署了未标记的分配（UID）数据，以弥合神经网络的培训和推理之间的差距。然而，这些方法在UID数据的可用性方面具有明确的限制和伪标签上的算法的依赖性。在此，我们提出了一种数据增强方法，通过使用缺乏上述问题的分发（OOD）数据来改善对抗和标准学习的泛化。我们展示了如何在理论上使用每个学习场景中的数据来改进泛化，并通过Cifar-10，CiFar-100和ImageNet的子集进行化学理论分析。结果表明，即使在似乎与人类角度几乎没有相关的图像数据中也是不希望的特征。我们还通过与其他数据增强方法进行比较，介绍了所提出的方法的优点，这些方法可以在没有UID数据的情况下使用。此外，我们证明该方法可以进一步改善现有的最先进的对抗培训。

深度神经网络（DNNS）最近在许多分类任务中取得了巨大的成功。不幸的是，它们容易受到对抗性攻击的影响，这些攻击会产生对抗性示例，这些示例具有很小的扰动，以欺骗DNN模型，尤其是在模型共享方案中。事实证明，对抗性训练是最有效的策略，它将对抗性示例注入模型训练中，以提高DNN模型的稳健性，以对对抗性攻击。但是，基于现有的对抗性示例的对抗训练无法很好地推广到标准，不受干扰的测试数据。为了在标准准确性和对抗性鲁棒性之间取得更好的权衡，我们提出了一个新型的对抗训练框架，称为潜在边界引导的对抗训练（梯子），该训练（梯子）在潜在的边界引导的对抗性示例上对对手进行对手训练DNN模型。与大多数在输入空间中生成对抗示例的现有方法相反，梯子通过增加对潜在特征的扰动而产生了无数的高质量对抗示例。扰动是沿SVM构建的具有注意机制的决策边界的正常情况进行的。我们从边界场的角度和可视化视图分析了生成的边界引导的对抗示例的优点。与Vanilla DNN和竞争性底线相比，对MNIST，SVHN，CELEBA和CIFAR-10的广泛实验和详细分析验证了梯子在标准准确性和对抗性鲁棒性之间取得更好的权衡方面的有效性。

有必要提高某些特殊班级的表现，或者特别保护它们免受对抗学习的攻击。本文提出了一个将成本敏感分类和对抗性学习结合在一起的框架，以训练可以区分受保护和未受保护的类的模型，以使受保护的类别不太容易受到对抗性示例的影响。在此框架中，我们发现在训练深神经网络（称为Min-Max属性）期间，一个有趣的现象，即卷积层中大多数参数的绝对值。基于这种最小的最大属性，该属性是在随机分布的角度制定和分析的，我们进一步建立了一个针对对抗性示例的新防御模型，以改善对抗性鲁棒性。构建模型的一个优点是，它的性能比标准模型更好，并且可以与对抗性训练相结合，以提高性能。在实验上证实，对于所有类别的平均准确性，我们的模型在没有发生攻击时几乎与现有模型一样，并且在发生攻击时比现有模型更好。具体而言，关于受保护类的准确性，提议的模型比发生攻击时的现有模型要好得多。

评估防御模型的稳健性是对抗对抗鲁棒性研究的具有挑战性的任务。僵化的渐变，先前已经发现了一种梯度掩蔽，以许多防御方法存在并导致鲁棒性的错误信号。在本文中，我们确定了一种更细微的情况，称为不平衡梯度，也可能导致过高的对抗性鲁棒性。当边缘损耗的一个术语的梯度主导并将攻击朝向次优化方向推动时，发生不平衡梯度的现象。为了利用不平衡的梯度，我们制定了分解利润率损失的边缘分解（MD）攻击，并通过两阶段过程分别探讨了这些术语的攻击性。我们还提出了一个Multared和Ensemble版本的MD攻击。通过调查自2018年以来提出的17个防御模型，我们发现6种型号易受不平衡梯度的影响，我们的MD攻击可以减少由最佳基线独立攻击评估的鲁棒性另外2％。我们还提供了对不平衡梯度的可能原因和有效对策的深入分析。