Photo of Matthias Fassl

Matthias Fassl

[maˈtiːas ˈfasl̩] · he/him

I am an interdisciplinary HCI researcher working on security, privacy, and safety. My current work focuses on technology-mediated stalking and intimate-image-based abuse in end-to-end-encrypted messengers.

I hold a Dr.-Ing. from Saarland University and bring a background in computer engineering, cultural & social anthropology, privacy advocacy, and EU cybercrime policy.

Research

Tech Policy & Design

Laws increasingly regulate our online identity, safety, and data, but companies often design around their spirit. I use design methods to make people more aware of their rights and give them more agency online.

Surveillance & Care

People care for each other through computers: ordering food, checking someone got home safely, switching on a light to say “I’m thinking of you.” But tools like Find My become surveillance when relationships change. I want to design care technologies that minimise that.

Security Snake Oil

Marketing for resistance technologies often promises more than the tools deliver, and it reshapes what people think good security looks like. I investigate these claims to correct misperceptions and see for whom resistance actually works.

Publications

2026
Shiza Ali, Wellington Esposito Barbosa, Matthias Fassl, Aditi Ganapathi, Jaron Mink, Adam J. Aviv
SOUPS 2026
Arwa Alsahdi, Jialiang Yan, Monica Kodwani, Matthias Fassl, Chris Kanich, Adam J. Aviv
PETS 2026
Adryana Hutchinson, Smirity Kaushik, Matthias Fassl, Adam J. Aviv
ACM CCS 2026
2025
Dañiel Gerhardt, Matthias Fassl
USENIX ;login: Online · July 2025
Dañiel Gerhardt, Matthias Fassl, Carolyn Guthoff, Adrian Dabrowski, Katharina Krombholz
USENIX Security 2025
2024
Matthias Fassl, Alexander Ponticello, Adrian Dabrowski, Katharina Krombholz
SOUPS 2024 · Poster
Dañiel Gerhardt, Matthias Fassl, Katharina Krombholz
SOUPS 2024 · Poster ★ Best Poster Runner-Up
2023
Matthias Fassl, Alexander Ponticello, Adrian Dabrowski, Katharina Krombholz
ACM CSCW 2023 ★ Honorable Mention ★ Methods Recognition
Anna-Marie Ortloff, Matthias Fassl, Alexander Ponticello, Florin Martius, Anne Mertens, Katharina Krombholz, Matthew Smith
ACM CHI 2023
Verena Distler, Matthias Fassl, Hana Habib, Katharina Krombholz, Gabriele Lenzini, Carine Lallemand, Vincent Koenig, Lorrie Faith Cranor
Book Chapter · Springer
2022
Matthias Fassl, Simon Anell, Sabine Houy, Martina Lindorfer, Katharina Krombholz
SOUPS 2022
Matthias Fassl, Lea Gröber, Katharina Krombholz
SOUPS 2022 · Poster
Lea Gröber, Matthias Fassl, Abhilash Gupta, Katharina Krombholz
SOUPS 2022 · Poster
2021
Verena Distler, Matthias Fassl, Hana Habib, Katharina Krombholz, Gabriele Lenzini, Carine Lallemand, Vincent Koenig, Lorrie Faith Cranor
ACM TOCHI · Vol. 28, Issue 6
Alexander Ponticello, Matthias Fassl, Katharina Krombholz
SOUPS 2021
Matthias Fassl, Michaela Neumayr, Oliver Schedler, Katharina Krombholz
ESORICS 2021 Workshop
Matthias Fassl, Lea Gröber, Katharina Krombholz
alt.CHI 2021
Matthias Fassl, Lea Gröber, Katharina Krombholz
ACM CHI 2021
Lea Gröber, Matthias Fassl, Abhilash Gupta, Katharina Krombholz
ACM CHI 2021
2018
Matthias Fassl
Master Thesis · TU Wien
Sabrina Burtscher, Matthias Fassl, Gabriel Grill
Progress Magazine · Vienna

Awards

Distinguished Reviewer Award
USENIX Security  ·  August 2026
Distinguished Reviewer Award
USENIX Security  ·  August 2025
Best Poster Runner-Up
SOUPS 2024  ·  August 2024
For "Will our Colleagues Detect the AirTag? Let's Check (Consensually)"
Google Trust & Safety Research Award
Google  ·  November 2023  ·  CISPA Helmholtz Center for Information Security
Best Paper Honorable Mention Award
ACM CSCW 2023  ·  October 2023  ·  CISPA Helmholtz Center for Information Security
Awarded to the top 3% of submissions  ·  For "Investigating Security Folklore: A Case Study on the Tor over VPN Phenomenon"

Press

Radio
Deutschlandfunk Warum Messenger-Kontakte nur selten verifiziert werdende EN ↗
Why messenger contacts are rarely verified
Nov 2023
Deutschlandfunk Is Tor still secure? Timing attacks on the anonymization networkde EN ↗
Expert commentary on the Boys Town case and the limits of Tor's anonymity guarantees
Oct 2024

Contact

Matthias Fassl
Collaborateur Scientifique, EPFL
Room BC 107 (Bâtiment BC)
Station 14, CH-1015 Lausanne, Switzerland

matthias.fassl@epfl.ch