Privacy-Enhancing Technologies - A Comprehensive Guide for Non-technical Practitioners

The widespread collection and use of data is transforming all facets of society, from scientific research to communication and commerce. The benefits of using data in decision-making are increasingly evident in tackling societal problems and understanding the world around us. At the same time, there are inherent vulnerabilities when sensitive data is stored, used, or shared, thereby creating an inherent friction between data use and the preservation of the human right to privacy.

Out of these concerns have arisen a plethora of proposed technical solutions for privacy protection. Often, such technologies fall under the purview of Privacy- Enhancing Technologies (PETs), a term that has been widely applied to any of a number of innovative solutions for realizing privacy in modern technical systems and their associated data processing practices.

In our previous and ongoing research, we have made a number of observations regarding PETs. Firstly, PETs are perceived as complex technologies largely residing in the academic sphere, and this complexity can serve as a barrier to adoption. Additionally, and as a result of such complexity, PET adoption remains low in practice; moreover, awareness of PETs and their underlying benefits and challenges also lags behind. Above all, we have learned that the adoption and implementation of PETs is far from a pure technical problem – various stakeholders, including non-technical professionals, must come together to bring PETs into action.

Based on these observations, we define our mission to be the accurate, concise, and understandable dissemination of PETs research to non-technical practitioners working in the area of privacy. We wish to serve as a seemingly much-needed bridge between privacy research and practice, where innovative research can be translated into motivating cases for practical adoption. We not only strive to break down the basics of prevalent PETs, but also to unite the motivation for PETs with ethical and social factors, as well as harmonize PET adoption with Privacy by Design practices. With this, we envision that PETs may become less mysterious and cryptic, and that awareness and confidence among practitioners may be bolstered.

We write this report in a period of time where data collection and usage occur at an unfathomable rate, most notably in the recent AI race, where increasingly larger models demand increasingly vast amounts of training data. While concerns of privacy have sparked a vibrant field of privacy research across the Machine Learning and Artificial Intelligence disciplines, such endeavors arguably pale in comparison to unfettered and unregulated data usage. Beyond the field of AI, practitioners struggle with reconciling privacy and regulatory demands with immediate business goals, where the former may be hard to justify from a utility and economic viewpoint.

In response to this, we hope that our report will not only demystify PETs by showcasing their promise and applicability, but we also hope to educate readers on the many factors that may serve to motivate the implementation of PETs, beyond mere regulatory pressures. This information is provided in an illustrative and comprehensible manner, and all insights in our report are grounded in findings from several practitioner-based studies.

We thank you for taking the time in reading our report, and we hope that you find it insightful!

— Alexandra, Stephen, and Florian
Garching, June 16, 2025