After verifying the correctness of the password, the keystroke dynamics-based authentication (KDA) system will verify the corresponding keystroke features. It provides additional security verification for alphanumeric-based and personal identification number-based authentication schemes that suffer from guessing and shoulder surfing attacks. Except for the original time features in the KDA schemes, two novel keystroke features are found in touch screen handheld mobile devices, which are called “pressure” features and “size” features. A computation efficient statistical classifier is built for low-power mobile devices to authenticate the user's identity. This paper analyzes the following combinations of features: (1) time features; (2) time features and pressure features; (3) time features and size features; and (4) all features combined. The result shows that the size features or the pressure features can effectively promote the utility of the KDA system in personal identification number-based authentication schemes for touch screen handled mobile devices. The combination of time features and pressure features is the best one for authenticating users. Copyright © 2013 John Wiley & Sons, Ltd.