I’m full professor of Data-Driven Internet Security in the Design and Analysis of Communication Systems (DACS) group at the Faculty of Electrical Engineering, Maths and Computer Science (EEMCS) at the University of Twente.

My research focuses on defending the Internet against malicious activity and on strengthening the security and resilience of the Internet by improving protocols and operations, and the deployment of new security protocols and mechanisms. I use an empirical approach to these challenges by performing global Internet-scale passive and active measurements.

Expertise

  • Computer Science

    • Domain Name System
    • Internet
    • Domains
    • Attack
    • Service
    • Public Key Infrastructure
    • Testbed
    • Distributed Denial of Service Attack

Organisations

Ancillary activities

  • Stichting NLnet LabsScientific Advisor
  • IPNSecretary IPN Equity, Diversity and Inclusion Working Group
  • SIDNMember strategy sounding board SIDN

My research focuses on defending the Internet against malicious activity and on strengthening the security and resilience of the Internet by improving protocols and operations, and the deployment of new security protocols and mechanisms. I use an empirical approach to these challenges by performing global Internet-scale passive and active measurements.

I currently have two particular areas of interest:

  • The Domain Name System (DNS) – after IP, DNS is the most critical protocol on the Internet, without which the Internet effectively stops working for most users. I explore the security of the DNS using large scale measurements and statistical analysis, for instance studying the effects of the deployment of the DNS Security Extensions (DNSSEC), both in the positive (added security) and the negative (larger potential for abuse in DDoS attacks) sense. DNS also plays an important role in other security issues on the Internet, such as botnets, phishing and malware.
  • Routing Security (RPKI) – much like other early core protocols of the Internet, the interdomain routing protocol BGP was not designed with security in mind. The Resource Public Key Infrastructure (RPKI) aims to remedy this by allowing resource holders to manage authorizations for their resources. Apart from having an interest in the gradual deployment of this technology on the global Internet, I am also interested in studying new applications that further enhance the security of the routing ecosystem.

My research is supported by SURF, the collaborative organisation for ICT in Dutch higher education and research, by the Netherlands Organisation for Scientific Research (NWO), by SIDN Fonds and by European Commission Framework Project grants.

Publications

2025

Load-Balancing Versus Anycast: A First Look at Operational Challenges (2025)IEEE transactions on network and service management (E-pub ahead of print/First online). Hendriks, R., Jonker, M., van Rijswijk-Deij, R. & Sommese, R.https://doi.org/10.1109/TNSM.2025.3636785LACeS: An Open, Fast, Responsible and Efficient Longitudinal Anycast Census System (2025)In IMC '25: Proceedings of the 2025 ACM Internet Measurement Conference (pp. 445-461). Association for Computing Machinery. Hendriks, R., Luckie, M., Jonker, M., Sommese, R. & van Rijswijk-Deij, R.https://doi.org/10.1145/3730567.3764484Safeguarding our digital society with empirical internet science (2025)[Book/Report › Inaugural speech]. University of Twente. van Rijswijk - Deij, R. M.Measuring The Impact of Post-Quantum Cryptography on Complex Applications: A Case Study on Federated Identity Management (2025)In 2025 9th Network Traffic Measurement and Analysis Conference (TMA). Fabrizio, G., Sperotto, A. & van Rijswijk - Deij, R. M.https://doi.org/10.23919/TMA66427.2025.11097002Locating and Enumerating Anycast: a Comparison of Two Approaches (2025)In ANRW 2025 - Proceedings of the 2025 Applied Networking Research Workshop (pp. 99-105). Association for Computing Machinery. Hendriks, R., Betzer, T., Du, B., Sommese, R., Jonker, M. & Van Rijswijk-Deij, R.https://doi.org/10.1145/3744200.3744783PQC for DNSSEC: a format size analysis on Falcon signatures (2025)In ANRW '25: Proceedings of the 2025 Applied Networking Research Workshop (pp. 143-149). Fabrizio, G., Koning, R., Lastdrager, E., Schutijser, C., Sperotto, A. & van Rijswijk - Deij, R. M.https://doi.org/10.1145/3744200.3744767From Scarcity to Opportunity: Examining Abuse of the IPv4 Leasing Market (2025)In Network Traffic Measurement and Analysis Conference 2025 (TMA'2025). IEEE. Degen, B., Du, B., Mok, R., Sommese, R., Jonker, M., van Rijswijk - Deij, R. M. & Claffy, k.LACeS: An Open, Fast, Responsible, and Efficient Longitudinal Anycast Census System (2025)[Working paper › Preprint]. ArXiv.org. Hendriks, R., Luckie, M., Jonker, M., Sommese, R. & van Rijswijk-Deij, R.https://doi.org/10.48550/arXiv.2503.20554Load-Balancing versus Anycast: A First Look at Operational Challenges (2025)[Working paper › Preprint]. ArXiv.org. Hendriks, R., Jonker, M., van Rijswijk-Deij, R. & Sommese, R.https://doi.org/10.48550/arXiv.2503.14351An Empirical Evaluation of Longitudinal Anycast Catchment Stability (2025)In Passive and Active Measurement: 26th International Conference, PAM 2025,Virtual event ,Proceedings (pp. 389-401) (Lecture Notes in Computer Science; Vol. 15567 LNCS). Springer (E-pub ahead of print/First online). Hendriks, R., Degen, B., Palinckx, B., Sommese, R. & van Rijswijk-Deij, R.https://doi.org/10.1007/978-3-031-85960-1_16

Research profiles

In the bachelor, I'm on the teaching team for the High-Tech Human Touch minor on Cybersecurity and Cybercrime, in which I teach the basics of Privacy and Information Security. In the master I teach courses on Internetworking, such as Internet Measurements and Advanced Networking.

I also regularly supervise bachelor and master theses, if you're looking for a topic feel free to contact me or drop by my office. I have an extensive network in industry, both in the Netherlands and abroad, so if you're looking for an internship assignment or an external master topic you can also contact me.

Affiliated study programs

Courses academic year 2025/2026

Courses in the current academic year are added at the moment they are finalised in the Osiris system. Therefore it is possible that the list is not yet complete for the whole academic year.

Courses academic year 2024/2025

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