Christian Knabenhans

Christian Knabenhans Christian Knabenhans

Ph.D. student in security and privacy

EPFL

About me

I’m a first-year doctoral student at EPFL, working broadly on security and privacy topics. I’m a recipient of a fellowship by EPFL’s doctoral school, and I’m splitting my first year between Alessandro Chiesa’s COMPSEC lab (working on zero-knowledge proof systems) and Carmela Troncoso’s SPRING lab (designing real-world systems to improve the security and privacy of at-risk users).

Before that, I worked on verifiable and robust Fully Homomorphic Encryption in Anwar Hithnawi’s Privacy-Preserving Systems Lab at ETH Zurich, and I hold a joint Master’s in Cyber-Security from EPFL and ETH.

At the moment, I’m mainly interested in improving the state-of-the-art in Privacy-Enhancing Technologies (particularly fully homomorphic encryption and zero-knowledge proofs). During my Bachelor’s and Master’s, I’ve also worked on static analysis and formal verification and privacy issues of machine learning.

In my free time, I’m involved in the non-profits ETH Cyber Group — Student Initiative and L’Association Francophone des Étudiants de Zurich. I also fence and rant about opera.

Publications

Verifiable Encodings for Secure Homomorphic Analytics
Holding Secrets Accountable: Auditing Privacy-Preserving Machine Learning
Verifiable Fully Homomorphic Encryption

Talks

Towards Robust FHE for the Real World
Verifiable FHE
Integrity Protection Challenges for Real-World FHE

News

24 May 2024 Veritas got accepted at CCS'24!

09 May 2024 Arc got accepted at USENIX'24!

12 Apr 2024 I’m giving a talk at Real World Crypto 🇨🇦 this year! I’ll also be at HACS and FHE.org in Toronto, and visiting UWaterloo.

01 Sep 2023 I’m starting my Ph.D. at EPFL!

06 Jul 2023 I’ll be at the EPFL Summer Research Institute, and at PETS and HotPETS in Lausanne next week

10 May 2023 I’m giving a talk at the Stanford security seminar next Wednesday, and I’ll be presenting a poster at S&P 🇺🇸!

25 Apr 2023 I’ll be attending the Lattices meet Hashes workshop at the Bernoulli Center at EPFL 🇨🇭

15 Apr 2023 I’ll be starting a Ph.D. at EPFL 🇨🇭 in September 2023!

11 Mar 2023 I’m going on a little academic world tour! I’ll be giving a guest lecture in Daniele Micciancio’s FHE course at UC San Diego and a talk at the Berkeley security seminar  🇺🇸, going to the Homomorphic Encryption Standards meeting in Seoul 🇰🇷, before giving a talk at to the FHE.org conference and attending Real World Crypto and HACS in Tokyo 🇯🇵.

09 Nov 2023 I graduated from ETH Zürich with a Master’s in Cyber Security! I’m not leaving ETH yet though, I’m spending the next few months doing research with Anwar Hithnawi’s PPS Lab.

Projects

Veritas - Verifiable Encodings for Secure Homomorphic Analytics
In the Veritas project, we investigated verifiable encodings for secure homomorphic analytics, i.e., cryptographic authenticators to guarantee the correctness of privacy-preserving computations performed using fully homomorphic encryption (FHE). Concretely, I fully implemented our two main approaches and variants thereof on top of the Lattigo FHE library.
Transfer Learning in Property Inference Attacks
Predicting the privacy loss from gradient updates in collaborative learning using new affinity measures derived from transfer learning.
Automatic Inference of Hyperproperties
Today, automated reasoning about program behavior is a well-established discipline in computer science, with a wide array of tools and techniques. In the most common scenario, the goal is to prove trace properties of programs, such as termination or functional correctness.