Adversarial training significantly improves adversarial robustness, but superior performance is primarily attained with large models. This substantial performance gap for smaller models has spurred active research into adversarial distillation (AD) to mitigate the difference. Existing AD methods leverage the teacher's logits as a guide. In contrast to these approaches, we aim to transfer another piece of knowledge from the teacher, the input gradient. In this paper, we propose a distillation module termed Indirect Gradient Distillation Module (IGDM) that indirectly matches the student's input gradient with that of the teacher. We hypothesize that students can better acquire the teacher's knowledge by matching the input gradient. Leveraging the observation that adversarial training renders the model locally linear on the input space, we employ Taylor approximation to effectively align gradients without directly calculating them. Experimental results show that IGDM seamlessly integrates with existing AD methods, significantly enhancing the performance of all AD methods. Particularly, utilizing IGDM on the CIFAR-100 dataset improves the AutoAttack accuracy from 28.06% to 30.32% with the ResNet-18 model and from 26.18% to 29.52% with the MobileNetV2 model when integrated into the SOTA method without additional data augmentation. The code will be made available.

使用间接梯度蒸馏模块（IGDM）通过匹配学生的输入梯度和教师的输入梯度来改善对抗性模型的性能，实验证明 IGDM 与现有的蒸馏方法无缝集成，显著提高了所有蒸馏方法的性能。

对抗鲁棒蒸馏的间接梯度匹配