The advent of end-to-end encrypted (E2EE) messaging and backup services has brought
new challenges for usable authentication. Compared to regular web services, the nature of …

Our everyday life depends more and more on online services and, therefore, access to
related user accounts. The security of user accounts, again, is tied to the security of the …

Nowadays, most online services offer different authentication methods that users can set up
for multi-factor authentication but also as a recovery method. This configuration must be …

In security engineering, including software security engineering, there is a well-known
design paradigm telling to prefer safe and secure defaults. The paper presents a …

Account access graphs have been proposed as a way to model relationships between user
credentials, accounts, and methods of access; they capture both multiple simultaneous …

Older adults are becoming more technologically proficient and use the internet to participate
actively in society. However, current best security practices can be seen as unusable by this …

As much as consumers express desires to safeguard their online privacy, they often fail to do
so effectively in reality. In my dissertation, I combine qualitative, quantitative, and design …

This thesis explores the field of user account configurations, focusing on analyzing various
setups to determine their security and accessibility. The initial findings indicate that the …