Emanuel von Zezschwitz

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A lot of research is being conducted into improving the us-<lb>ability and security of phone-unlocking. There is however<lb>a severe lack of scientific data on users’ current unlocking<lb>behavior and perceptions. We performed an online survey<lb>(n = 260) and a one-month field study (n = 52) to gain<lb>insights into real world (un)locking behavior of(More)
Graphical password systems based upon the recall and reproduction of visual patterns (e.g. as seen on the Google Android platform) are assumed to have desirable usability and memorability properties. However, there are no empirical studies that explore whether this is actually the case on an everyday basis. In this paper, we present the results of a real(More)
Authentication in public spaces is a risky task. Frauds on cash machines (ATMs) are not uncommon nowadays. The biggest group of attacks is observation attacks, which focus on recording the input done by the users. In this work, we present VibraPass, a system created to be resilient against observation attacks using tactile feedback provided by the users'(More)
This paper presents <i>BoD Shapes</i>, a novel authentication method for smartphones that uses the back of the device for input. We argue that this increases the resistance to shoulder surfing while remaining reasonably fast and easy-to-use. We performed a user study (<i>n</i>=24) comparing BoD Shapes to PIN authentication, Android grid unlock, and a front(More)
Most of today's smartphones and tablet computers feature touchscreens as the main way of interaction. By using these touchscreens, oily residues of the users' fingers, smudge, remain on the device's display. As this smudge can be used to deduce formerly entered data, authentication tokens are jeopardized. Most notably, grid-based authentication methods,(More)
In this paper, we present the results of two studies on the influence of mobile devices on authentication performance and password composition. A pre-study in the lab (<i>n</i> = 24) showed a lower performance for password-entry on mobile devices, in particular on smartphones. The main study (<i>n</i> = 450) showed a trend that alphanumeric passwords are(More)
Modern smartphones carry a huge amount of sensitive data. This includes personal information, business information or account information of various online services. In a situation where sharing the device with another person is unavoidable, this data might be in danger. In this paper, we present insights into up-to-date mobile device sharing behavior. We(More)
We performed a systematic evaluation of the shoulder surfing susceptibility of the Android pattern (un)lock. The results of an online study (n=298) enabled us to quantify the influence of pattern length, line visibility, number of knight moves, number of overlaps and number of intersections on observation resistance. The results show that all parameters(More)
In this paper, we present SwiPIN, a novel authentication system that allows input of traditional PINs using simple touch gestures like up or down and makes it secure against human observers. We present two user studies which evaluated different designs of SwiPIN and compared it against traditional PIN. The results show that SwiPIN performs adequately fast(More)