Cyrill Krähenbühl

Postdoctoral Research Associate

Cyrill Krähenbühl’s research focuses on public key infrastructures (PKI) and path aware networking (PAN). He completed his Ph.D. under the guidance of Adrian Perrig in 2023 at ETH Zürich where he also earned his master’s degree in computer science.

We all make use of PKI when we look at web pages or use secure communication systems. Although the majority of our communication is secured through PKI-based systems, the protocols and infrastructures have grown organically and have still numerous shortcomings. Krähenbühl’s research introduces flexibility into trust foundation of PKIs, enabling end users and certificate owners to define their trust preferences. He designed systems that enable trust agility, while increasing the security yet retaining the high availability of the systems.

Path-aware networking provides more transparency and control to network participants, in particular the network endpoints. Knowledge and (partial) control of the forwarding path can significantly improve a network’s efficiency through in-network multipath and allows endpoints to optimize for the needs of individual applications. In the area of path-aware networking, Krähenbühl contributed to documenting the deployment methodologies, defined and categorized path properties, and extended path selection in the SCION architecture to enable fine-grained intra-domain paths with specific policies.

During his Ph.D., Krähenbühl actively collaborated with industry partners and other research groups, and helped analyze real-world security-critical systems and design concrete security recommendations. He published at multiple top tier venues, such as NDSS, USENIX Security, and CoNEXT, where he was given the best paper and best presentation award. In addition to his work in the research community, he actively engaged with standardization bodies such as the IETF, in particular with the path aware networking research group, where he co-authored a guidance RFC on path properties in path aware networks.

Krähenbühl can be reached at , 320A Sherrerd Hall.