A novel nonintrusive user authentication method based on touch gestures for smartphones

Novel nonintrusive authentication mechanisms for smartphones have recently been investigated to complement existing protection mechanisms. A major reason is that a nonintrusive approach can continually authenticate users without interrupting their operations. In this paper, a novel approach to nonintrusive authentication of smartphone users involving flick gestures is proposed. Sixteen histogram-based features of flick gestures, including five novel features related to the habitual touch positions of a user, were used for authentication. Empirical results based on 51 participants indicated that the proposed approach was feasible. The equal error rate of the proposed approach was approximately 4.37% ∼ 5.13% when the histogram-based features were calculated based on 30 flicks and decreased to approximately 2.35% ∼ 2.99% for features based on 60 flicks. In addition, the experimental results revealed that the five novel features proposed are effective. Possible applications and limitations of the proposed approach are discussed.