Jacob Leon Kröger

With many million users across all age groups and income levels, video games have become the world's leading entertainment industry. Behind the fun experience they provide, it goes largely unnoticed that modern game devices pose a serious threat to consumer privacy. To illustrate the industry's potential for illegitimate surveillance and user profi...

Despite years of heavy criticism, privacy self-management (i.e., the principle that people individually manage their privacy via notice and choice) remains the standard of privacy protection throughout the Western world. Building on previous research, this article provides an overview and classification of the manifold obstacles that render privacy...

Accelerometers are sensors for measuring acceleration forces. They can be found embedded in many types of mobile devices, including tablet PCs, smartphones, and smartwatches. Some common uses of built-in accelerometers are automatic image stabilization, device orientation detection, and shake detection. In contrast to sensors like microphones and c...

Internet-connected devices, such as smartphones, smartwatches, and laptops, have become ubiquitous in modern life, reaching ever deeper into our private spheres. Among the sensors most commonly found in such devices are microphones. While various privacy concerns related to microphone-equipped devices have been raised and thoroughly discussed, the...

Technologies to measure gaze direction and pupil reactivity have become efficient, cheap, and compact and are finding increasing use in many fields, including gaming, marketing, driver safety, military, and healthcare. Besides offering numerous useful applications, the rapidly expanding technology raises serious privacy concerns. Through the lens o...

The strict and consequential legal distinction between “personal” and “non-personal” data needs to be questioned. The scope of data protection laws is typically limited to personal data, i.e., information “relating to an identified or identifiable natural person” (Art. 4 (1) GDPR). Thus, the data subject rights and data controller obligations presc...

Digital technology has revolutionized how political ads are delivered and consumed, giving political campaigns increased possibilities to target and tailor their messaging to specific audiences—a practice known as political microtargeting (PMT). While PMT has potential benefits for society, it also entails significant risks that have yet to be adeq...

Most of the literature on political microtargeting (PMT) draws from experiments and case studies in the Global North while examples from the Global South have not been collected and collated regularly on an international level. Therefore, this chapter presents brief reviews of PMT applications in Africa (Kenya, Nigeria), South/Southeast Asia (Phili...

This chapter examines the risks and potential benefits for society posed by political microtargeting (PMT). Potential benefits: (1) Ad relevance and diversification of content, (2) efficiency of campaign activity, and (3) ability to reach and activate specific population segments. Better functioning political communication could, in turn, activate...

We call on state and non-state actors around the world to devote attention to political microtargeting (PMT) and its impacts in their local contexts. Understanding PMT and persuasive technologies better is important to encourage benevolent uses and regulate against harmful applications. We have developed a set of recommendations that are specified...

Efforts to investigate the role of political microtargeting (PMT) and any plans for regulation should consider certain context-and country-specific factors that may influence the impacts of PMT. In an attempt to understand which drivers influence the information environment around elections, we outlined five factors that are particularly relevant f...

While most countries still have no comprehensive legislation in place to address political microtargeting (PMT), efforts to regulate and legislate around the phenomenon are quickly emerging around the world. In order to define the material scope of any regulation on PMT, one fundamental question is how to legally define “political advertisement”. T...

With many million users across all age groups and income levels, video games have become the world’s leading entertainment industry. Behind the fun experience they provide, it goes largely unnoticed that modern game devices pose a serious threat to consumer privacy. To illustrate the industry’s potential for illegitimate surveillance and user profi...

In the face of ubiquitous surveillance and people’s loss of control over their personal data, informational privacy is widely perceived as irretrievably “dead”. Illustrating the complexity of the problem and contributing to the search for realistic solutions, this cumulative dissertation deals with privacy threats posed by mobile apps, web tracking...

Under current privacy laws, most forms of personal data processing are authorized via consent, leaving the cost-benefit calculation to the individual data subject. However, given the realities of today’s data economy, people are usually not in a position to make truly free and informed privacy choices. Thus, the notice-and-choice approach does not...

To secure a minimum level of accountability and control under the given complexities of data processing, regulation should strive for the greatest possible transparency at all stages of the data processing lifecycle. As many technological trends and privacy threats cannot be averted per se, transparency and accountability are in some respect means...

Journalistic investigations have revealed that some of the world's leading tech policy institutes significantly depend on funding from Big Tech, causing potential conflicts of interest and threatening academic freedom. The power of corporations to intimidate and suppress critical voices from academia is also well illustrated by recent cases where s...

Certain categories of personal data are widely viewed as more sensitive than others – and receive particular protection by legal and technical privacy safeguards. However, even seemingly non-sensitive data can be exploited for malicious ends, resulting in considerable harm for the data subject and other affected parties. Additionally, through the l...

Anonymous data is typically not protected by privacy law. However, many dangerous data practices are possible without real names attached to the data, including user profiling, behavioral ad targeting, personalized tailoring of persuasive (e.g., political) messages, price discrimination, and more. Anonymous data can feed machine learning algorithms...

Under current privacy laws, most forms of personal data processing are authorized via consent, leaving the cost-benefit calculation to the individual data subject. However, given the realities of today’s data economy, people are usually not in a position to make truly free and informed privacy choices. Thus, the notice-and-choice approach does not...

Inferences drawn from patterns and correlations in collected data are becoming an increasingly efficient way to access intimate information about unsuspecting individuals. Legal analyses have revealed that the GDPR does not reliably protect individuals against the privacy threats posed by inferential analytics. Due to vague wording, the law’s appli...

Embedded in mobile devices, private homes, workplaces, and public spaces, sensors have become ubiquitous in modern society. While improving our lives in many ways, the widespread use of sensors also raises serious privacy concerns. Data from everyday sensors often contains intimate personal information and is accessible to various possibly untruste...

Recent decades have produced a wide variety of technical tools for privacy protection. However, the hopes placed in these tools are often inflated. Overestimating the protective effect of privacy-enhancing technologies can be dangerous and may lead to a false sense of security. This chapter stresses that the following aspects need to be born in min...

Through voice characteristics and manner of expression, even seemingly benign voice recordings can reveal sensitive attributes about a recorded speaker (e. g., geographical origin, health status, personality). We conducted a nationally representative survey in the UK (n = 683, 18-69 years) to investigate people's awareness about the inferential pow...

Even after decades of intensive research and public debates, the topic of data privacy remains surrounded by confusion and misinformation. Many people still struggle to grasp the importance of privacy, which has far-reaching consequences for social norms, jurisprudence, and legislation. Discussions on personal data misuse often revolve around a few...

Smartphones und Smartwatches, unsere täglichen mobilen Begleiter, stecken voller Sensoren, die viel über uns verraten können — viel mehr, als die meisten Nutzer:innen ahnen. Was das genau für Daten sind, die durch Sensoren erfasst werden, und welche Informationen sich daraus ableiten lassen, erforscht Autor Jacob Leon Kröger, Doktorand der Forschun...

Smartphones and smartwatches, our daily mobile companions, are full of sensors that can reveal a lot about us – much more than most users realize. Author Jacob Leon Kröger, a doctoral student in the research group “Responsibility and the Internet of Things”, examines exactly what data is collected by sensors and what information can be derived from...

The German Corona-Warn-App (CWA) is one of the most controversial tools to mitigate the Corona virus spread with roughly 25 million users. In this study, we investigate individuals’ knowledge about the CWA and associated privacy concerns alongside different demographic factors. For that purpose, we conducted a study with 1752 participants in German...

Despite 2-factor authentication and other modern approaches, authentication by password is still the most commonly used method on the Internet. Unfortunately, as analyses show, many users still choose weak and easy-to-guess passwords. To alleviate the significant effects of this problem, systems often employ textual or graphical feedback to make th...

EU data protection laws grant consumers the right to access the personal data that companies hold about them. In a first-of-its-kind longitudinal study, we examine how service providers have complied with subject access requests over four years. In three iterations between 2015 and 2019, we sent subject access requests to vendors of 225 mobile apps...

Web tracking is found on 90 % of common websites. It allows online behavioral analysis which can reveal insights to sensitive personal data of an individual. Most users are not aware of the amout of web tracking happening in the background. This paper contributes a sonification-based approach to raise user awareness by conveying information on web...

Besides various other privacy concerns with mobile devices, many people suspect their smartphones to be secretly eavesdropping on them. In particular, a large number of reports has emerged in recent years claiming that private conversations conducted in the presence of smartphones seemingly resulted in targeted online advertisements. These rumors h...

Targeted advertising is an inherent part of the modern Web as we know it. For this purpose, personal data is collected at large scale to optimize and personalize displayed advertisements to increase the probability that we click them. Anonymity and privacy are also important aspects of the World Wide Web since its beginning. Activists and developer...

A growing number of sensors, embedded in wearables, smart electric meters and other connected devices, is surrounding us and reaching ever deeper into our private lives. While some sensors are commonly regarded as privacy-sensitive and always require user permission to be activated, others are less protected and less worried about. However, experim...

Die Onlinehandelsbranche befindet sich inmitten eines tiefgreifenden strukturellen Wandels, der durch verschiedene wirtschaftliche und technologische Trends getrieben wird. Da immer mehr Onlinehändler Schwierigkeiten haben, mit den neuesten Entwicklungen Schritt zu halten, wird von Experten bereits eine drastische Konsolidierung der jungen Branche...