  Certified patch defenses can guarantee robustness of an image classifier to
arbitrary changes within a bounded contiguous region. But, currently, this
robustness comes at a cost of degraded standard accuracies and slower inference
times. We demonstrate how using vision transformers enables significantly
better certified patch robustness that is also more computationally efficient
and does not incur a substantial drop in standard accuracy. These improvements
stem from the inherent ability of the vision transformer to gracefully handle
largely masked images. Our code is available at
https://github.com/MadryLab/smoothed-vit.
