As user demand and cost benefits of natural user interface (NUI) technologies are hastening their adoption, computing devices that come equipped with these interfaces are becoming ubiquitous. Consequently, authentication mechanisms on them are becoming an essential security component to enable a wider range of applications that need higher requirements of security as well as privacy. In this talk we will survey the landscape of “point-of-entry” user-device authentication mechanisms based on behavioral biometrics that require a natural user interaction using gestural or non-gestural interaction for access. This interaction includes 2-D touch gestures, 3-D gestures, voice, eye tracking, and braincomputer interaction. We will analyze their potential security and usability promises and issues, and discuss plausible solutions that could be pursued in future work.