Date of Award


Document Type


Degree Name

Doctor of Philosophy (PhD)


Computer Engineering and Sciences

First Advisor

Heather Crawford

Second Advisor

Katrina Ellis

Third Advisor

William Allen

Fourth Advisor

Keith Gallagher


The popularity of wearable devices (WDs) has been growing rapidly in recent years because of the convenience they add to users lives. Although WDs may be considered an extension of mobile computing devices (e.g., smartphones), their form factor is very different: WDs are always available and expected to be accessible, and they often lack typical input means such as a keyboard. Therefore, they need to be treated, in terms of authentication, differently than other computing devices since we cannot simply apply possibly unsuitable traditional authentication methods such as password that were designed for other modalities. In this dissertation, we introduce the Authentication Framework for Wearable Devices (AFWD) which provides a model to create trustworthy, continuous, transparent, and user-accepted authentication methods for WDs. The AFWD respects the WDs unique form factor by authenticating wearers transparently and continuously. It also respects the WDs limitations such as the lack of input methods by exploiting the current WD wearers use pattern (e.g., behavioral biometrics) to verify that they are the owner of the device. The AFWD is designed to be hardware and software independent, as well as be used with various types of biometric modalities which makes it flexible in light of WDs and biometric future changes.