  Smartphones store a significant amount of personal and private information,
and are playing an increasingly important role in people's lives. It is
important for authentication techniques to be more resistant against two known
attacks called shoulder surfing and smudge attacks. In this work, we propose a
new technique called 3D Pattern. Our 3D Pattern technique takes advantage of a
new input paradigm called pre-touch, which could soon allow smartphones to
sense a user's finger position at some distance from the screen. We implement
the technique and evaluate it in a pilot study (n=6) by comparing it to PIN and
pattern locks. Our results show that although our prototype takes about 8
seconds to authenticate, it is immune to smudge attacks and promises to be more
resistant to shoulder surfing.
