IEEE SIGNAL PROCESSING MAGAZINE, VOL. X, NO. X, MONTH 2016 1 Continuous User Authentication on Mobile Devices: Recent Progress and Remaining Challenges Vishal M. Patel, Senior Member, IEEE,, Rama Chellappa, Fellow, IEEE, Deepak Chandra, and Brandon Barbello Abstract Recent developments in sensing and communication technologies have led to an explosion in the use of mobile devices such as smartphones and tablets. With the increase in the use of mobile devices, one has to constantly worry about the security and privacy as the loss of a mobile device could compromise personal information of the user. To deal with this problem, continuous authentication (also known as active authentication) systems have been proposed in which users are continuously monitored after the initial access to the mobile device. In this paper, we provide an overview of different continuous authentication methods on mobile devices. We discuss the merits and drawbacks of available approaches and identify promising avenues of research in this rapidly evolving field. Index Terms Mobile authentication, continuous authentication, biometrics, active authentication, transparent au- thentication. Vishal M. Patel is with the department of Electrical and Computer Engineering (ECE) at Rutgers University, Piscataway, NJ 08854 USA
[email protected]. Rama Chellappa is with the Center for Automation Research, UMIACS, University of Maryland, College Park, MD 20742 USA
[email protected]. Deepak Chandra, and Brandon Barbello are with Google Inc, Mountain View, CA 94043 USA fdchandra,
[email protected]. July 3, 2016 DRAFT IEEE SIGNAL PROCESSING MAGAZINE, VOL. X, NO. X, MONTH 2016 2 I. INTRODUCTION Traditional methods for authenticating users on mobile devices are based on explicit authentication mechanisms such as passwords, pin numbers or secret patterns.