Felix Günther

Welcome

I am a Research Scientist in the Foundational Cryptography group at IBM Research Zurich. My research focuses on real-world cryptographic systems, contributing to the security of Internet security protocols like TLS, QUIC, or Signal and their cryptographic building blocks.

Previously, I was a senior researcher in the Applied Cryptography Group at ETH Zurich led by Kenny Paterson. Earlier and supported by a research fellowship of the German Research Foundation (DFG), I was a postdoctoral researcher at ETH Zurich and in the Security and Cryptography Group at UC San Diego working with Mihir Bellare. I obtained my Ph.D. in Computer Science from Technische Universität Darmstadt in 2018 under the supervision of Marc Fischlin in the Cryptography and Complexity Theory (Cryptoplexity) Group, and, earlier, M.Sc. degrees in Computer Science and IT Security from TU Darmstadt. I am a member of the IACR.

Research Interests

As an applied cryptographer, I am interested in how cryptography enables computer and network security, and in provable cryptographic security more specifically. My work aims to narrow the gap between the theoretical understanding and practical security of real-world cryptographic systems. I especially focus on Internet cryptographic protocols such as TLS, QUIC, or Signal, studying their security and concrete parameters, as well as constructing new cryptographic building blocks for improved security. In doing so, my work broadly encompasses formal modeling of cryptographic properties and assumptions, designing provably-secure cryptographic systems, rigorous security analyses of real-world protocols and primitives, and contributing to security standards.

News

2024-08-13

Our paper Obfuscated Key Exchange [8] (with Douglas Stebila and Shannon Veitch) was accepted to CCS 2024.

Academic Career and Education

since 2023	Research Scientist at IBM Research Europe – Zurich
2022–2023	Senior researcher in the Applied Cryptography Group at ETH Zurich Working with: Prof. Kenneth G. Paterson
2019–2022	Postdoctoral researcher in the Applied Cryptography Group at ETH Zurich Working with: Prof. Kenneth G. Paterson
2018–2019	Postdoctoral researcher in the Security and Cryptography Group at UC San Diego Working with: Prof. Mihir Bellare
2018	Postdoctoral researcher in the Cryptoplexity Group at TU Darmstadt Working with: Prof. Marc Fischlin
2013–2018	Ph.D. in Computer Science, TU Darmstadt Thesis: Modeling Advanced Security Aspects of Key Exchange and Secure Channel Protocols [46] Advisor: Prof. Marc Fischlin
2010–2013	M.Sc. in Computer Science, TU Darmstadt M.Sc. in IT Security, TU Darmstadt
2007–2010	B.Sc. in Computer Science, TU Darmstadt

Grants, Awards, and Honors

2018–2020	DFG (German Research Foundation) Research Fellowship Grant Foundations and Real-World Aspects of Secure Cryptographic Connections, carried out at UC San Diego and ETH Zurich
2019	ACM SIGSAC Doctoral Dissertation Award for Outstanding PhD Theses in Computer and Information Security
2019	Dr.-Heinz-Sebiger Dissertation Award on Data Protection and IT Security of the DATEV-Stiftung Zukunft foundation
2019	Best paper award at ESORICS 2019 for [24]
2019	ERCIM (European Research Consortium for Informatics and Mathematics) STM WG Award for the Best Ph.D. Thesis on Security and Trust Management
2019	Runner-up for the CAST/German Informatics Society Doctoral Dissertation Award in IT Security (CAST/GI Promotionspreis IT-Sicherheit)
2017, 2018	Collaboration Award 2017 for [25] and 2018 for [5] of the collaborative research center CROSSING at TU Darmstadt
2018	Best lecture award for lecture Real World Crypto, TU Darmstadt, summer term 2017 (teaching assistant, award for overall lecture by the computer science student's body, based on evaluations by students)
2015	Best student paper award at ACISP 2015 for [34]
2011	CAST Advancement Award IT Security (CAST-Förderpreis IT-Sicherheit): 2nd prize in category "Bachelor and Study Theses" for my bachelor thesis [48]
2007–2013	Scholarship from the German National Academic Foundation (Studienstiftung des deutschen Volkes)

Professional Activities

Program Chairs

• Security Standardisation Research Conference (SSR) 2023

Program Commitee (PC) Memberships

• ACM CCS 2025, 2024 (ACM Conference on Computer and Communications Security)
• CRYPTO 2022, 2020, 2019 (Annual International Cryptography Conference)
• EUROCRYPT 2025, 2022 (Annual International Conference on the Theory and Applications of Cryptology and Information Security)
• IEEE S&P 2023 (IEEE Symposium on Security and Privacy)
• SSR 2022, 2020 (Security Standardisation Research Conference)
• ACM WWW 2025 (The Web Conference)
• EPIQ 2021 (Workshop on the Evolution, Performance and Interoperability of QUIC)
• QUIPS 2020 (QUIC Privacy and Security Workshop)

Award Committee Memberships

• CAST/GI Promotionspreis IT-Sicherheit 2024, 2022

Ph.D. Committee Memberships

• NTNU Trondheim, Norway, 2024

Peer Reviewing for Scientific Conferences and Journals

• 2024: EUROCRYPT, ASIACRYPT
• 2023: EUROCRYPT
• 2022: SCN, ACM CCS
• 2021: EUROCRYPT, CRYPTO, ACM CCS
• 2020: Journal of Cryptology, ASIACRYPT
• 2019: EUROCRYPT, ACM CCS, Journal of Cryptology
• 2018: ACM CCS
• 2017: EUROCRYPT, PKC, ACISP, Latincrypt
• 2016: CRYPTO
• 2015: Latincrypt, ACM CCS
• 2014: INFOCOM, TCC, ACNS, ASIACRYPT, Elsevier Information Processing Letters
• 2013: Elsevier Computer Communications Journal

Grant Reviewing

• DFG – German Research Foundation 2023

General Chairs & Organization of Events

June 2024	SKECH 2024 Workshop Organizer
May 2024	EUROCRYPT 2024 Affiliated Events Chair
April 2023	SSR 2023 Conference General Chair
May 2019	EUROCRYPT 2019 Affiliated Events Chair

Other Activities

Sep 2018

Lecturer at the ECRYPT-NET School on Integrating Advanced Cryptography with Applications

Contributions to Standards, Research Impact, and Media Attention

• Co-Editor of the IRTF CFRG working group Internet-Draft on Usage Limits on AEAD Algorithms [1]
• EDHOC security analysis [12] informed the IETF LAKE working group, acknowledged in the EDHOC RFC 9528 standard
• Robust channel work on QUIC and DTLS 1.3 [3] informed the IETF QUIC and TLS working groups, contributor to the QUIC RFC 9001 and DTLS 1.3 RFC 9147 standards
• TLS 1.3 security analyses [32,41,31,29] informed the IETF TLS working group, contributor to the TLS 1.3 RFC 8446 standard
• Security analysis and attacks on the ISO/IEC 25185-1.2 protocol PLAID [35,7] were covered by golem.de, Matthew Green's Blog, Schneier on Security, Slashdot, The Register

Teaching

ETH Zurich

spring semester 2025	Applied Cryptography (co-lecturing with Florian Tramèr)
spring semester 2024	Applied Cryptography (co-lecturing with Kenny Paterson, Florian Tramèr)
spring semester 2023	Applied Cryptography (co-lecturing with Kenny Paterson)
autumn semester 2022	Teaching assistant for the course Informatik I by Manuela Fischer and Ralf Sasse
spring semester 2022	Teaching assistant and lecture contribution for the course Applied Cryptography by Kenny Paterson
autumn semester 2021	Teaching assistant for the course Informatik I by Carlos Cotrini and Ralf Sasse
autumn semester 2021	Lecture contribution to the course Information Security Lab by Kenny Paterson
spring semester 2021	Teaching assistant and lecture contribution for the course Applied Cryptography by Kenny Paterson
autumn semester 2020	Co-coordination of the seminar Current Topics in Information Security by Srdjan Capkun, Kenny Paterson, and Adrian Perrig
spring semester 2020	Co-coordination of the seminar Current Topics in Cryptography by Kenny Paterson, Dennis Hofheinz, and Ueli Maurer
spring semester 2020	Lecture contribution to the course Applied Cryptography by Kenny Paterson

University of California San Diego

winter quarter 2019

TLS Crypto Seminar Graduate-level (informal) seminar with both lectures and paper presentations

Technische Universität Darmstadt

winter term 2018/2019	Organization of the graduate-level seminar Reading the Crypto Classics
summer term 2018	Teaching assistant for the lecture Real World Crypto by Marc Fischlin
summer term 2018	Organization of the graduate-level seminar Reading the Crypto Classics
winter term 2017/2018	Organization of the graduate-level seminar Reading the Crypto Classics
summer term 2017	Teaching assistant for the lecture Real World Crypto by Marc Fischlin (Best lecture award for overall lecture, by the computer science student's body, based on evaluations by students)
winter term 2016/2017	Teaching assistant for the research seminar Research-Oriented Cryptography by Marc Fischlin
winter term 2015/2016	Teaching assistant for the lecture Functional and Object-oriented Programming Concepts (Funktionale und objektorientierte Programmierkonzepte, ex. Grundlagen der Informatik 1) by Marc Fischlin
winter term 2013/2014	Teaching assistant for the lecture Introduction to Computer Science 1 (Grundlagen der Informatik 1) by Marc Fischlin
winter term 2011/2012	Tutor for the lecture Introduction to Cryptography (Einführung in die Kryptographie) by Marc Fischlin

Advising

• Younis Khalil (Master thesis, Jan 2023–Aug 2023). Implementing a Secure Cloud Storage System.
  Co-Advisors: Kenneth G. Paterson, Matilda Backendal. ETH Zurich, Switzerland.
• Younis Khalil (Semester project, Aug 2022–Jan 2023). Implementing a Puncturable Key Wrapping Library.
  Co-Advisors: Kenneth G. Paterson, Matilda Backendal. ETH Zurich, Switzerland.
• Marc Ilunga Tshibumbu Mukendi (Master thesis, Jan 2022–Aug 2022). Analysis of the EDHOC Lightweight Authenticated Key Exchange Protocol.
  Co-Advisors: Kaveh Razavi, Kenneth G. Paterson. ETH Zurich, Switzerland.
• Radwa Sherif Abdelbar (Master thesis, Mar 2021–Sep 2021). Post-Quantum KEM-based TLS with Pre-Shared Keys.
  Co-Advisors: Kenneth G. Paterson, Patrick Towa. ETH Zurich, Switzerland.
• Nicolas Klose (Master thesis, Oct 2020–Mar 2021). Characterizing Notions for Secure Cryptographic Channels.
  Co-Advisor: Kenneth G. Paterson. ETH Zurich, Switzerland.
• Mihael Liskij (Master thesis, Sep 2020–Mar 2021). A Survey of TLS 1.3 0-RTT Usage.
  Co-Advisor: Kenneth G. Paterson. ETH Zurich, Switzerland.
• Alexandre Poirrier (Master thesis, Sep 2020–Mar 2021). Continuous Authentication in Secure Messaging.
  Co-Advisor: Kenneth G. Paterson, Benjamin Dowling. ETH Zurich, Switzerland.
• Matilda Backendal (Master thesis, Jan 2019–Jun 2019). Puncturable Symmetric KEMs for Forward-Secret 0-RTT Key Exchange.
  Co-Advisor: Thomas Johansson. Lund University, Sweden.