Thanks to recent advances in deep neural networks (DNNs), face recognition
systems have become highly accurate in classifying a large number of face
images. However, recent studies have found that DNNs could be vulnerable to
adversarial examples, raising concerns about the robustness of such systems.
Adversarial examples that are not restricted to small perturbations could be
more serious since conventional certified defenses might be ineffective against
them. To shed light on the vulnerability to such adversarial examples, we
propose a flexible and efficient method for generating unrestricted adversarial
examples using image translation techniques. Our method enables us to translate
a source image into any desired facial appearance with large perturbations to
deceive target face recognition systems. Our experimental results indicate that
our method achieved about $90$ and $80\%$ attack success rates under white- and
black-box settings, respectively, and that the translated images are
perceptually realistic and maintain the identifiability of the individual while
the perturbations are large enough to bypass certified defenses.