Emanuel von Zezschwitz

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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)
A lot of research is being conducted into improving the us-ability and security of phone-unlocking. There is however a severe lack of scientific data on users' current unlocking behavior and perceptions. We performed an online survey (n = 260) and a one-month field study (n = 52) to gain insights into real world (un)locking behavior of smartphone users. One(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)
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 XSide, an authentication mechanism that uses the front and the back of smartphones to enter stroke-based passwords. Users can switch sides during input to minimize the risk of shoulder surfing. We performed a user study (n = 32) to explore how switching sides during authentication affects usability and security of the system. The(More)
We present the results of an MTurk survey (n=383) on the reasons for using and not using biometric authentication systems on smartphones. We focused on Apple's Touch ID as well as Android's Face Unlock as they are the most prevalent systems on the market. For both systems, we categorized the participants as a) current users, b) former users that deactivated(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)
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)
In this paper, we present a concept using fake cursors to disguise on-screen password entry. We performed two user studies with different amounts of dummy cursors and differently colored cursors. The results show that dummy cursors significantly improve security. At the same time, decrease in performance is kept within an acceptable range. Depending on the(More)
In this paper, we investigate the evolutionary change of user-selected passwords. We conducted one-on-one interviews and analyzed the complexity and the diversity of users' passwords using different analysis tools. By comparing their first-ever created passwords to several of their currently used passwords (e.g. most secure, policy-based), we were able to(More)