A roadmap to continuous biometric authentication on mobile devices

Mobile devices nowadays contain a variety of personal or even business-related information that is worth being protected from unauthorized access. Owners of such devices should use a passcode or unlock pattern to secure such important assets, but since these techniques are being perceived as annoying barriers, locked devices are not standard. But even if such authentication mechanisms are used, they are very easy to circumvent. Biometric methods are promising applications to secure mobile devices in an user-friendly, discreet way. Based on embedded sensors like gyroscope, accelerometer or microphones, which are state-of-the-art sensors for mobile devices, behavioral biometric approaches appear even more attractive for user verification than physiological methods like fingerprints or face recognition. So far many biometric approaches have been presented. After a short overview of relevant representatives, we discuss these methods based on their applicability and limitations. Our findings are summarized and presented as a roadmap to provide a foundation for future research.