Keystroke authentication is a well known method to secure the mobile devices. Especially, the increasing amount of personal and sensitive data stored on these devices makes a secure authentication system necessary. Traditional security techniques like the four-digit PIN-input are insufficient and do not correspond to the present password standards. A keystroke behavior based authentication system could increase the security. Different researches have been published based on keystroke authentication systems with traditional PC keypads. But the keystroke behavior on touchscreens, as they are nowadays used on smartphones, are not analysed before.