Graph neural networks (GNNs) which apply the deep neural networks to graph data have achieved significant performance for the task of semi-supervised node classification. However, only few work has addressed the adversarial robustness of GNNs. In this paper, we first present a novel gradient-based attack method that facilitates the difficulty of tackling discrete graph data. When comparing to current adversarial attacks on GNNs, the results show that by only perturbing a small number of edge perturbations, including addition and deletion, our optimization-based attack can lead to a noticeable decrease in classification performance. Moreover, leveraging our gradient-based attack, we propose the first optimization-based adversarial training for GNNs. Our method yields higher robustness against both different gradient based and greedy attack methods without sacrificing classification accuracy on original graph.

本文提出了基于梯度的攻击方法，以解决离散图数据的难点，并基于此提出了第一个面向图神经网络的基于优化的对抗训练，可以提高不同梯度和贪心攻击方法的鲁棒性，同时不牺牲原始图的分类准确性。

图神经网络的拓扑攻击与防御：优化视角