Research — Home

The Usable Security and Privacy Group explores the design of secure systems that blend with the way in which users interact with computing devices. In particular, our research focuses on behavioral biometrics, social engineering, usable security in smart homes, novel authentication concepts, physiological security and security in mixed reality.

We are also involved in funded projects, such as ubihave (DFG), Biometrics++ (ZD.B), Scalable Biometrics (DFG), Voice of Wisdom (DTEC) and MuQuaNet (DTEC).

In order to be able to support (junior) research with appropriate hardware, our group also manages the BehAVRLab.

You can find a selection of our individual research projects here.

How Unique do we Move?

Past work showed great promise in biometric user identification and authentication through exploiting specific features of specific body parts. We investigate human motion across the whole body, to explore what parts of the body exhibit more unique movement patterns, and are more suitable to identify users in general. We collect and analyze full-body motion data across various activities (e.g., sitting, standing), handheld objects (uni- or bimanual), and tasks (e.g., watching TV or walking). Our analysis shows, e.g., that gait as a strong feature amplifies when carrying items, game activity elicits more unique behaviors than texting on a smartphone, and motion features are robust across body parts whereas posture features are more robust across tasks. Our work provides a holistic reference on how context affects human motion to identify us across a variety of factors, useful to inform researchers and practitioners of behavioral biometric systems on a large scale.

PriView

We present and evaluate a concept to visualize privacy-invasive devices in users’ vicinity. In particular, we contribute (a) a mobile application, capable of detecting smart devices using a thermal camera and (b) a VR application presenting suitable scenarios

Effects of Body Normalizations on Behavioral Biometrics

In this paper we investigate how well users can be identified in VR in realistic, task-driven scenarios using spatial movements. In particular, we investigate the role of users’ physiology by virtually altering and normalizing their body proportions, showing that by doing so the identification accuracy can be enhanced by 38%.

SpatialProto

This paper presents SpatialProto, an in-situ spatial prototyping system for mixed reality, which lowers the barrier for designers to engage in spatial prototyping. SpatialProto lets users record animated objects of the real world, extract relevant elements, and directly place and transform these recordings in their physical environment.

Hidden Interactions

We present and explore the concept of hidden interaction techniques which supports interaction in situations in which the use of personal devices is not socially acceptable or where nearby people present a privacy risk. In particular, two applications are presented and evaluated. HiddenHaptic conveys information through vibrotactile cues on smartphones. HiddenWrite allows text messages to be composed on smart watches.

Behavioral Biometrics in VR

We investigate body motion as behavioural biometrics for virtual reality. In particular, we look into which behaviour is suitable to identify a user.

ARtention

We present ARtention, a design space for gaze interaction specifically tailored for in-situ AR information interfaces. It highlights three important dimensions to consider in the UI design of such gaze-enabled applications: transitions from reality to the virtual interface, from single- to multi-layer content, and from information consumption to selection tasks.

TangibleSphere

We demonstrate how this physicality can be brought to VR by means of TangibleSphere – a tracked, low-cost physical object that can (a) be rotated freely and (b) is overlaid with a virtual display.

Intentional Behavior Modifications

This paper presents the first study on understanding users’ ability to modify their typing behaviour when entering passwords on smartphones.

Device Confidence and Re-Authentication in Continuous Authentication

We developed a novel approach to enable users to anticipate the need for re-authentication with two indicators: (1) a long term indicator shows the current DCL and its development over time, and (2) a short term indicator announces that re-authentication is imminent.

EyeGaze in Security and Privacy Applications

We present a holistic view on gaze-based security applications. In particular, we canvassed the literature and classify the utility of gaze in security applications into a) authentication, b) privacy protection, and c) gaze monitoring during security critical tasks.

Virtual Field Studies

We investigate the feasibility of using virtual reality (VR) as a test-bed to evaluate deployments of public displays. Specifically, we investigate whether results from virtual field studies, conducted in a virtual public space, would match the results from a corresponding real-world setting.

Designing Voice Assistant Personalities for Automotive UIs

This paper investigates personalized voice characters for incar speech interfaces. In particular, we report on how we designed different personalities for voice assistants and compared them in a real world driving study.

Personal Mobile Messaging in Context

We augment text messaging with information about users and contexts. We present and reflect on lessons learned from three field studies, in which we deployed augmentation concepts as prototype chat apps in users’ daily lives.