  DNA sequencing is becoming increasingly commonplace, both in medical and
direct-to-consumer settings. To promote discovery, collected genomic data is
often de-identified and shared, either in public repositories, such as OpenSNP,
or with researchers through access-controlled repositories. However, recent
studies have suggested that genomic data can be effectively matched to
high-resolution three-dimensional face images, which raises a concern that the
increasingly ubiquitous public face images can be linked to shared genomic
data, thereby re-identifying individuals in the genomic data. While these
investigations illustrate the possibility of such an attack, they assume that
those performing the linkage have access to extremely well-curated data. Given
that this is unlikely to be the case in practice, it calls into question the
pragmatic nature of the attack. As such, we systematically study this
re-identification risk from two perspectives: first, we investigate how
successful such linkage attacks can be when real face images are used, and
second, we consider how we can empower individuals to have better control over
the associated re-identification risk. We observe that the true risk of
re-identification is likely substantially smaller for most individuals than
prior literature suggests. In addition, we demonstrate that the addition of a
small amount of carefully crafted noise to images can enable a controlled
trade-off between re-identification success and the quality of shared images,
with risk typically significantly lowered even with noise that is imperceptible
to humans.
