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Title of the thesis: Usable Security and Privacy of Apps in Mobile Ecosystems

Thesis defender: Amel Bourdoucen  
Opponent: Dr. PhD Serge Egelman, University of California, Berkeley
Custos: Prof. Janne Lindqvist, Aalto University School of Science

Today’s digital life is built on ecosystems of connected devices and apps. Smartphones, laptops, and wearables all collect and share personal data. While these services bring convenience, they also create challenges: privacy and security settings are scattered, difficult to understand, and sometimes misleading.

This thesis examined how people experience and manage privacy across three common contexts: default apps in popular ecosystems, online gaming platforms, and collaborative family apps such as Apple’s Family Sharing and Google's Family Link. The purpose of this work was to understand where users struggle, how design choices contribute to these struggles, and what improvements could make privacy easier to manage.

The research found that many users believe they have disabled data collection when, in reality, hidden settings continue to share information. In online games, players were often nudged into oversharing personal data through game design choices, sometimes leading to risks such as harassment or unwanted tracking. In collaborative family apps, unclear roles and accidental sharing created tensions between parents, partners, and children.

The main conclusion is that privacy failures are not simply the result of “careless users.” Instead, they often stem from system complexity and design shortcomings. The thesis shows that users are not always the weakest link.

The research contributes new insights to the fields of Human–Computer Interaction (HCI) and usable security by reframing privacy as both an individual and a collective concern. The findings can be applied by technology companies, app designers, and policymakers to improve system transparency, improve privacy controls, and support families and communities in managing their digital lives.

In short, this thesis demonstrates that privacy is continuously negotiated in everyday interactions—whether through setting up a device, playing a game, or sharing within a family—and offers practical recommendations for building more user-friendly and trustworthy digital ecosystems.

Keywords: privacy, security, default apps, mobile ecosystems, collaborative family apps, online games, dark design patterns

References: 

Helsingin sanomat:
Forbes:

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Thesis available for public display 7 days prior to the defence at .