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)
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)
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)
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)
Energetic charged particle detectors characterize a portion of the plasma distribution function that plays critical roles in some physical processes, from carrying the currents in planetary ring currents to weathering the surfaces of planetary objects. For several low-resource missions in the past, the need was recognized for a low-resource but highly(More)
The LHC [1] will be supplied, via the SPS, with protons from the pre-injector chain comprising Linac2, PS Booster (PSB) and PS. These accelerators have undergone a major upgrading programme [2] during the last five years so as to meet the stringent requirements of the LHC. These imply that many high-intensity bunches of small emittance and tight spacing (25(More)
Touchscreens, the dominant input type for mobile phones, require unique authentication solutions. Gesture passwords have been proposed as an alternative ubiquitous authentication technique. Prior security analysis has relied on inconsistent measurements such as mutual information or shoulder surfing attacks.We present the first approach for measuring the(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)
To achieve breakthroughs in the areas of heliospheric and magnetospheric energetic neutral atom (ENA) imaging, a new class of instruments is required. We present a high angular resolution ENA imager concept aimed at the suprathermal plasma populations with energies between 0.5 and 20 keV. This instrument is intended for understanding the spatial and(More)