A cybersecurity researcher in the forests of Värmland, Sweden, that cares deeply about privacy, human rights, and democracy. Working as a senior lecturer (docent ≈ associate professor) in Computer Science at Karlstad University, Sweden. I have collaborated on a range of topics in projects funded by EU {H2020, FP6, FP7, TEMPUS}, Google, Mullvad VPN, the NLnet Foundation, the Swedish Foundation for Strategic Research, the Swedish Internet Foundation, the Swedish Knowledge Foundation, and more. An engineer and scientist at heart—and trying not to forget that—by building as well as understanding things. Recovering applied cryptographer trying to broaden my horizons.

My focus in 2024

DRIVE: Research Profile on Secure Low-Latency Communication

A long-term research profile funded by the Knowledge Foundation of Sweden. Working mostly with partner Mullvad VPN on high-performance low-latency secure communication solutions.

KIPL: Karlstad Internet Privacy Lab and Maybenot

Starting up a R&D lab in Karlstad in the same group as Mullvad VPN. The first task is to accelerate the development of Maybenot and associated tooling for traffic analysis defenses that is the foundation of DAITA.

Selected publications

In chronological order:

• Tobias Pulls and Ethan Witwer. Maybenot: A Framework for Traffic Analysis Defenses. WPES 2023.
• Rasmus Dahlberg and Tobias Pulls. Timeless Timing Attacks and Preload Defenses in Tor’s DNS Cache. USENIX Security 2023.
• Matthias Beckerle, Jonathan Magnusson, and Tobias Pulls. Splitting Hairs and Network Traces: Improved Attacks Against Traffic Splitting as a Website Fingerprinting Defense. WPES 2022.
• Rasmus Dahlberg, Tobias Pulls, Tom Ritter, and Paul Syverson. Privacy-Preserving & Incrementally-Deployable Support for Certificate Transparency in Tor. PETS 2021.
• Tobias Pulls and Rasmus Dahlberg. Website Fingerprinting with Website Oracles. PETS 2020.
• Benjamin Greschbach, Tobias Pulls, Laura M. Roberts, Philipp Winter, and Nick Feamster. The Effect of DNS on Tor’s Anonymity. NDSS 2017.
• Tobias Pulls and Roel Peeters. Balloon: A Forward-Secure Append-Only Persistent Authenticated Data Structure. ESORICS 2015.
• Philipp Winter, Tobias Pulls, and Juergen Fuss. ScrambleSuit: A Polymorphic Network Protocol to Circumvent Censorship. WPES 2013.

Supervision

Actively involved in research collaboration with two PhD students:

• Bolaji, working on eBPF security together with Red Hat Research.
• Jonathan, working on DNS together with the Swedish Internet Foundation.

Regularly offer topics, supervision, and examination of Bachelor’s and Master’s theses. My goal is to offer at least one project every semester.

PhD alumni

People I have been part of supervising during their now completed PhD studies:

• Rasmus, working on CT and Tor with the Swedish Foundation for Strategic Research.
• Nurul, co-supervising on measuring the privacy friendliness of Android Apps.

Education

Many hours of teaching at all levels in a broad range of courses over the years. Currently teacher and examiner for Internet Security and Privacy (DVAD23). Three years experience on study programme administration at the undergraduate level. Development of course material and training teachers on site in Bishkek, Kyrgyzstan, and Tashkent, Uzbekistan (EU TEMPUS). Contract teaching on Vulnerability Analysis for a Swedish company on site in Shanghai, China.

Service

Core member of the Tor Project. Secretary of the Swedish digital rights organization DFRI. Program committee {CCS,PETS,NordSec,WPES}. Vice program chair PETS 2025. Program chair NordSec 2024. Publication chair for PETS 2019-2021. Have served as pre-examiner, opponent, and committee member at PhD level.

Contact

For work, see contact info at my staff page at Karlstad University. Privately, <firstname> [at] <lastname> .name or mobile/Signal at 70 601 53 18.