Mind how you answer me!
Mauro Conti, Irina Zachia-Zlatea, Bruno Crispo · 2011
In this paper we propose a new biometric measure to authenticate the user of a smartphone: the movement the user performs when answering (or placing) a phone call. The biometric measure leverages features that are becoming commodities in new smartphones, i.e. accelerometer and orientation sensors. We argue that this new biometric measure has a unique feature. That is, it allows a transparent authentication (not requiring an additional specific interaction for this) to check that the user that is answering (or placing) a phone call is the one authorized to do that. At the same time, this biometric measure can also be used as a non transparent authentication method, e.g. the user may need to move the phone as if answering a call, in order to unlock the phone to get access to SMSs or emails. As a consequence of being a biometric measure, an adversary that spies on the movement (e.g. captures it with a camera) and tries to replicate it, will not be granted access to the phone.