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.
Although touch-screen laptops are increasing in popularity, users still do not comfortably rely on touch in these environments, as current software interfaces were not designed for being used by the finger. In this paper, we first demonstrate the benefits of using touch as a complementary input modality along with the keyboard and mouse or touchpad in a laptop setting. To alleviate the frustration users experience with touch, we then design two techniques, TouchCuts, a single target expansion technique, and ,i>TouchZoom, i>, a multiple target expansion technique. Both techniques facilitate the selection of small icons, by detecting the finger proximity above the display surface, and expanding the target as the finger approaches. In a controlled evaluation, we show that our techniques improve performance in comparison to both the computer mouse and a baseline touch-based target acquisition technique. We conclude by discussing other application scenarios that our techniques support.