Interpreting Adversarial Robustness: A View from Decision Surface in Input Space
This work addresses the challenge of improving adversarial robustness for neural networks, offering a novel approach that avoids the computational cost of adversarial training.
The authors tackled the problem of understanding adversarial robustness in neural networks by showing that the geometry of decision surfaces in input space correlates with robustness, and they proposed an indicator and training method to enhance robustness without adversarial training.
One popular hypothesis of neural network generalization is that the flat local minima of loss surface in parameter space leads to good generalization. However, we demonstrate that loss surface in parameter space has no obvious relationship with generalization, especially under adversarial settings. Through visualizing decision surfaces in both parameter space and input space, we instead show that the geometry property of decision surface in input space correlates well with the adversarial robustness. We then propose an adversarial robustness indicator, which can evaluate a neural network's intrinsic robustness property without testing its accuracy under adversarial attacks. Guided by it, we further propose our robust training method. Without involving adversarial training, our method could enhance network's intrinsic adversarial robustness against various adversarial attacks.