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The increasing use of smartphones as personal computing platforms to access personal information has stressed the demand for secure and usable authentication techniques, and for constantly protecting privacy. Smartphone sensors can measure users’ unique behavioral characteristics when they interact with smartphones, based on different habits, gestures, and angle preferences of touch actions. This paper investigates the reliability and applicability of using motion-sensor behavior for active and continuous smartphone authentication across various operational scenarios, and presents a systematic evaluation of the distinctiveness and permanence properties of the behavior. For each sample of sensor behavior, kinematic information sequences are extracted and analyzed, which are characterized by statistic-, frequency-, and wavelet-domain features, to provide accurate and fine-grained characterization of users’ touch actions. A Markov-based decision procedure, using one-class learning techniques, is developed and applied to the feature space for performing authentication. Analyses are conducted using the sensor data of 520 200 touch actions from 102 subjects across various operational scenarios. Extensive experiments show that motion-sensor behavior exhibits sufficient discriminability and stability for active and continuous authentication, and can achieve a false-rejection rate of 5.03% and a false-acceptance rate of 3.98%. Additional experiments on usability to operation length, sensitivity to application scenario, scalability to user size, contribution to different sensors, and response to behavior change are provided to further explore the effectiveness and applicability. We also implement an authentication system into the Android system that can react to the presence of the legitimate user. [ABSTRACT FROM PUBLISHER]

The increasing use of touchscreen smartphones to access sensitive and privacy data has given rise to the need of secure and usable authentication technique. Smartphone users have their own unique behavioral characteristics when performing touch operations. These personal characteristics are reflected on different rhythm, strength, and angle preferences of touch-interaction behavior. This paper investigates the reliability and applicability on the usage of users’ touch-interaction behavior for active authentication on smartphones. For each common type of touch operations, both static and dynamic features are extracted and analyzed for fine-grained characterization of users’ touch behavior. Classification techniques (nearest neighbor, neural network, support vector machine, and random forest) are applied to the feature space for performing the task of active authentication. Analyses are conducted using data from around 134 900 touch operations of 71 participants in real-world scenarios, and the authentication performance is evaluated across various types of touch operations, varying operation lengths, different application tasks, and different application scenarios. The extensive experimental results are included to show that touch-interaction behavior exhibits sufficient discriminability and stability among smartphone users for active authentication, and achieves equal-error rates between 1.72% and 9.01% for different types of touch operations with the operation length of 11; the authentication accuracies improve when having long observation or small timespan between the training and testing phases, and express more reliably and stably in a specific task than in the free task. We also discuss a number of avenues for additional research that we believe are necessary to advance the state-of-the-art in this area. [ABSTRACT FROM PUBLISHER]

Behavior-based user authentication with pointing devices, such as mice or touchpads, has been gaining attention. As an emerging behavioral biometric, mouse dynamics aims to address the authentication problem by verifying computer users on the basis of their mouse operating styles. This paper presents a simple and efficient user authentication approach based on a fixed mouse-operation task. For each sample of the mouse-operation task, both traditional holistic features and newly defined procedural features are extracted for accurate and fine-grained characterization of a user's unique mouse behavior. Distance-measurement and eigenspace-transformation techniques are applied to obtain feature components for efficiently representing the original mouse feature space. Then a one-class learning algorithm is employed in the distance-based feature eigenspace for the authentication task. The approach is evaluated on a dataset of 5550 mouse-operation samples from 37 subjects. Extensive experimental results are included to demonstrate the efficacy of the proposed approach, which achieves a false-acceptance rate of 8.74%, and a false-rejection rate of 7.69% with a corresponding authentication time of 11.8 seconds. Two additional experiments are provided to compare the current approach with other approaches in the literature. Our dataset is publicly available to facilitate future research. [ABSTRACT FROM PUBLISHER]