Can Directed Graph Neural Networks be Adversarially Robust?
Zhichao Hou Xitong Zhang Wei Wang Charu C. Aggarwal Xiaorui Liu
The existing research on robust Graph Neural Networks (GNNs) fails to
acknowledge the significance of directed graphs in providing rich information
about networks' inherent structure. This work presents the first investigation
into the robustness of GNNs in the context of directed graphs, aiming to
harness the profound trust implications offered by directed graphs to bolster
the robustness and resilience of GNNs. Our study reveals that existing directed
GNNs are not adversarially robust. In pursuit of our goal, we introduce a new
and realistic directed graph attack setting and propose an innovative,
universal, and efficient message-passing framework as a plug-in layer to
significantly enhance the robustness of GNNs. Combined with existing defense
strategies, this framework achieves outstanding clean accuracy and
state-of-the-art robust performance, offering superior defense against both
transfer and adaptive attacks. The findings in this study reveal a novel and
promising direction for this crucial research area. The code will be made
publicly available upon the acceptance of this work.