Abstract
Security on smartphones has become a substantial topic since the amount of security relevant data and information stored on them has been increasing. While the password is commonly used as a traditional approach for user authentication, it suffers from a security-usability trade-off dilemma. Accordingly, the keystroke dynamics authentication approach can provide ease of use to the user as well as robust security. This paper investigates the feasibility of utilising user-typing behaviours on touchscreen keypads for the authentication process via free-text keystroke dynamics. In constructing the timing vectors, three timing features are used: hold time, flight time and digraph duration. Additionally, Euclidian and Manhattan distances were utilised to find the degree of similarity between the user's login data and user's profile. An Android application was developed and evaluated through an experimental study. Thus, we achieved a very encouraging result, as we were able to show that applying the free-text method indeed influences the accuracy of user authentication on a touchscreen device.