Title: CAT: Collaborative Adversarial Training. Abstract: Adversarial training can improve the robustness of neural networks. Previous adversarial training methods focus on a single training strategy and do not consider the collaboration between different training strategies. In this paper, we find different adversarial training methods have distinct robustness for sample instances. For example, an instance can be correctly classified by a model trained using standard adversarial training (AT) but not by a model trained using TRADES, and vice versa.  Based on this phenomenon, we propose a collaborative adversarial training framework to improve the robustness of neural networks. Specifically, we simultaneously use different adversarial training methods to train two robust models from scratch. We input the adversarial examples generated by each network to the peer network and use the logit of the peer network to guide the training of its network. Collaborative Adversarial Training (CAT) can improve both robustness and accuracy. Finally, Extensive experiments on CIFAR-10 and CIFAR-100 validated the effectiveness of our method.
CAT achieved new state-of-the-art robustness without using any additional data on CIFAR-10 under the Auto-Attack benchmark.