Privacy-Enhancing Technologies

Digital technologies have become an essential part of our day-to-day lives. While often beneficial, these technologies also bring great privacy risks. In this course, you will learn how to mitigate these risks by designing privacy-friendly systems and how to evaluate the privacy protections offered by systems.

To reason about the privacy of systems you will learn how to define desirable privacy properties and how to reason about privacy attackers. Privacy can be violated both at the application level (i.e., what data parties exchange) as well as on the meta-data level (i.e., how parties exchange data). You will learn about techniques to offer protection at both of these layers.

On the application layer, we’ll discuss cryptographic techniques such as secure multi-party computation, homomorphic encryption, and anonymous authentication that together can be used to ensure privacy at the application layer. We will also discuss data anonymisation techniques such as k-anonymity and differential privacy to enable privacy-friendly data publishing. On the meta-data level, we’ll explore techniques for anonymous communication, censorship resistance, (browser) tracking, and location privacy.

At the end of this course you will be able to:

• Explain basic building blocks for designing privacy-friendly systems
• Combine these building blocks to solve simple problems while maintaining privacy
• Evaluate the privacy of simple proposed systems.

Prerequisites

The privacy-enhancing technologies class is an advanced lecture. You will learn a lot about how to design and analyse privacy-friendly systems, but this is not an easy 6EC course. A basic understanding of security and cryptography (as taught for example in CySec1/CySec2 or the Security course) is essential to be able to follow the material in this course. If you have not mastered this material we strongly recommend you to take this course next year instead.

Schedule

Main Lecture: Tuesday from 2pm c.t. to 4pm
Exercises/Discussion: Tuesday from 4pm s.t. to 5pm
Room: E9.1 (CISPA building), room 0.05 (main lecture room)

Schedule

The following schedule is subject to small changes.

• April 8: Introduction to Privacy
• April 15: Secure Multi-Party Computation (remote)
• April 22: Crypto Recap + Zero-knowledge Proofs (recorded)
• Apr 29: Attribute-Based Credentials
• May 6: Tracking
• May 13: Fully-Homomorphic Encryption
• May 20: Anonymous Communication
• May 27: Censorship Resistance
• June 3: no class
• June 10: Website Fingerprinting
• June 17: Anonymization / Protected Data Release (online)
• June 24: Differential Privacy
• July 1: (Bonus) End-to-End Privacy-Friendly Systems

Format

The course will be hybrid, but attending the lectures and exercise sessions is strongly recommended for UdS students. Attending online only possible in exceptional cases. We will publish recordings of the lectures. We will not publish recordings of the exercise/discussion sessions. Learning to reason about privacy is difficult. We strongly recommend that you attend the exercise/discussion sessions to practice your reasoning skills.

 

Exercise Class / Office Hours

We offer office hours to answer questions regarding the content of the lecture, exercise sheets, and projects. Feel free to drop by in person or remotely if you have any questions.

In Person

Times: Wednesday, 3pm s.t. -- 4pm
Location: CISPA building (E9.1), Room 1.02

Remote

The remote office hours are primarily intended for those who cannot attend the in-person office hour. Please book a time slot in advance via the sheet linked in the Materials section.

Times: Wednesday, 2pm s.t. -- 3pm
Location: Zoom (Link in Materials section)

 

Grading

The final grade for this course consists of 60% for the final exam and 40% for the projects.

Grading subject to small changes. Details will be explained in the first lecture.

Projects

As part of this class you will work on three projects to implement and evaluate a privacy-preserving system. The projects contribute 40% to the final grade: 10% for the first project and 15% for each of the second and third projects. There is no option to improve the grade for the projects.

Final Exam

Exam date: August 1, 2025, 9:30am s.t. -- 11:30am
Format: Written exam
Location: E1.3, HS001 

The final written exam tests your understanding of the material covered in the class, exercises, and projects. You must receive a passing grade on the exam alone. If you do, the exam is graded and contributes 60% to the final grade.

The re-exam will take place on:

Exam date: September 19, 2025, 9:30am s.t. -- 11:30am
Format: Written Exam
Location: E9.1 (CISPA building), room 0.05 (main lecture room)