Robust machine learning formulations have emerged to address the prevalent
vulnerability of deep neural networks to adversarial examples. Our work draws
the connection between optimal robust learning and the privacy-utility tradeoff
problem, which is a generalization of the rate-distortion problem. The saddle
point of the game between a robust classifier and an adversarial perturbation
can be found via the solution of a maximum conditional entropy problem. This
information-theoretic perspective sheds light on the fundamental tradeoff
between robustness and clean data performance, which ultimately arises from the
geometric structure of the underlying data distribution and perturbation
constraints.