Alexander De Luca

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Password patterns, as used on current Android phones, and other shape-based authentication schemes are highly usable and memorable. In terms of security, they are rather weak since the shapes are easy to steal and reproduce. In this work, we introduce an implicit authentication approach that enhances password patterns with an additional security layer,(More)
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 systems for public terminals and thus public spaces have to be fast, easy and secure. Security is of utmost importance since the public setting allows manifold attacks from simple shoulder surfing to advanced manipulations of the terminals. In this work, we present <i>EyePassShapes</i>, an eye tracking authentication method that has been(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)
CityFlocks is a mobile system enabling visitors and new residents in a city to tap into the knowledge and experiences of local residents, so as to gather information about their new environment. Its design specifically aims to lower existing barriers of access and facilitate social navigation in urban places. This paper presents a design case study of a(More)
Automated teller machine (ATM) frauds are increasing drastically these days. When analyzing the most common attacks and the reasons for successful frauds, it becomes apparent that the main problem lies in the PIN based authentication which in itself does not provide any security features (besides the use of asterisks). That is, security is solely based on a(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)
Authentication today mostly relies on passwords or personal identification numbers (PINs). Therefore the average user has to remember an increasing amount of PINs and passwords. Unfortunately, humans have limited capabilities for remembering abstract alphanumeric sequences. Thus, many people either forget them or use very simple ones, which implies several(More)
With the increase of automated teller machine (ATM) frauds, new authentication mechanisms are developed to overcome security problems of personal identification numbers (PIN). Those mechanisms are usually judged on speed, security, and memorability in comparison with traditional PIN entry systems. It remains unclear, however, what appropriate values for(More)