Gradeigh Clark

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This paper studies the security and memorability of free-form multitouch gestures for mobile authentication. Towards this end, we collected a dataset with a generate-test-retest paradigm where participants (N=63) generated free-form gestures, repeated them, and were later retested for memory. Half of the participants decided to generate one-finger gestures,(More)
Gestures are a topic of increasing interest in authentication, but successfully implementing them as a security layer requires reliable gesture recognition. So far, much work focuses on new ways to recognize gestures, leaving discussion on the viability of recognition in an authentication scheme to the background. It's as yet unclear how gesture recognition(More)
App permissions detail the privacy-sensitive access to users' location, contact information, network access, and more. In this paper, we draw from the motivational work of McDonald and Cranor [18] on web privacy policies to investigate the opportunity cost for users and the United States if people <i>would</i> read these permission screens on mobile devices(More)
Free-form gesture passwords have been introduced as an alternative mobile authentication method. Text passwords are not very suitable for mobile interaction, and methods such as PINs and grid patterns sacrifice security over usability. However, little is known about how free-form gestures perform in the wild. We present the first field study (N=91) of(More)
Digital currencies represent a new method for exchange -- a payment method with no physical form, made real by the Internet. This new type of currency was created to ease online transactions and to provide greater convenience in making payments. However, a critical component of a monetary system is the people who use it. Acknowledging this, we present(More)
Digital currencies represent a new method for exchange and investment that differs strongly from any other fiat money seen throughout history. A digital currency makes it possible to perform all financial transactions without the intervention of a third party to act as an arbiter of verification; payments can be made between two people with degrees of(More)
An electromagnetic coil gun with three stages of accelerating coils is designed and built. Conventional projectile propulsion mechanisms include the use of compressed air/spring or explosion which places theoretical limits on the maximum muzzle velocity governed by laws of thermodynamics. The electromagnetic coil gun, on the other hand, explores the use of(More)
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