Before revision:  In this paper, we survey more than 140 recent behavioral biometric-based approaches for continuous user authentication, including motion-based methods ( 27 studies), gait-based methods ( 23 studies), keystroke dynamics-based methods (20 studies), touch gesture-based methods (29 studies), voice-based methods (16 studies), and multimodal-based methods ( 33 studies).
After revision:  In this paper, we survey more than 140 recent behavioral biometric-based approaches for continuous user authentication, including motion-based methods ( 28 studies), gait-based methods ( 23 studies), keystroke dynamics-based methods (20 studies), touch gesture-based methods (29 studies), voice-based methods (16 studies), and multimodal-based methods ( 33 studies).