Ismael Khoffi is the co-founder and CTO of Celestia Labs. Khoffi has a background in research and hands-on engineering and has worked in a range of areas including the higher education industry and small to large enterprises. ^[1]

Education

Khoffi completed his academic studies at the University of Bonn from 2003 to 2013, earning a Diplom (equivalent to a Master's degree) in Mathematics and Computer Science. He achieved an excellent grade of 1.1, with major focuses on Discrete Mathematics & Optimization, Cryptography & Information Security, and Relational Databases. ^[2]

His thesis, titled "Discrete FlipIt: Analysis and Experiments," was conducted under the guidance of advisors Prof. Dr. Joachim von zur Gathen and Prof. Nitin Saxena. This research delved into the analysis and experimentation of Discrete FlipIt. ^[2]

Career

Khoffi has held the position of Co-Founder and Chief Technology Officer (CTO) at Celestia Labs since October 2019. ^[3]

Celestia is the first modular blockchain Network and the core idea is to decouple consensus from execution.

In a subsequent role as a Senior Software Engineer at Informal Systems on a freelance basis from January 2020 to January 2021, Khoffi contributed to the development of the Tendermint light client in Rust. His involvement extended to Validator UG (haftungsbschränkt) as a Gesellschafter from November 2019 to December 2020 and as a Senior Software Engineer at Interchain Foundation, again on a freelance basis, from September 2019 to January 2020, where he played a role in enhancing the Tendermint light client in Rust. ^[3]

In the public sector, he served as an External Evaluation Expert for the European Commission from April 2019 to December 2019. During this time, Khoffi evaluated grant applications and provided advice in the field of "deep tech." His academic contributions include a role as an Independent Researcher (Fellowship) at Technische Universität Berlin from July 2019 to November 2019, where he collaborated on a Stellar-related research project. ^[3]

Beyond this, Khoffi engaged in pro bono consulting as a Security Consultant at Verisart from January 2018 to November 2019, focusing on IT security, cryptography, key management, and blockchain infrastructure. In earlier roles, he served as a Software Engineer at All in Bits (AiB) / Tendermint, contributing to various projects related to Tendermint's core technology. His career also includes roles in security research and technology at Digital Catapult, Google, and academic and research institutions such as EPFL, Fraunhofer FKIE, and The University of Bonn. ^[3]

Earlier, Khoffi was involved in software development roles at HYPE Innovation and Detecon International GmbH. Additionally, he contributed as a teaching assistant at Universität Bonn, where he assisted in courses on Linear Algebra and Calculus. ^[3]

Publications

Some of his publications include: ^[1]

• Kirill Nikitin, Eleftherios Kokoris Kogias, Philipp Svetolik Jovanovic, Linus Gasser, Nicolas Gailly, Ismail Khoffi, Justin Cappos, Bryan Ford. CHAINIAC: Proactive Software-Update Transparency via Collectively Signed Skipchains and Verified Builds. In Usenix Security Symposium, 2017.
• Ewa Syta, Philipp Jovanovic, Eleftherios Kokoris Kogias, Nicolas Gailly, Linus Gasser, Ismail Khoffi, Michael J. Fischer, Bryan Ford. Scalable bias-resistant distributed randomness. In IEEE S&P, 2017.
• Eleftherios Kokoris-Kogias, Linus Gasser, Ismail Khoffi, Philipp Jovanovic, Nicolas Gailly, Bryan Ford. Managing Identities Using Blockchains and CoSi. In HotPETs, 2016.
• Eleftherios Kokoris-Kogias, Philipp Jovanovic, Nicolas Gailly, Ismail Khoffi, Linus Gasser, Bryan Ford. Enhancing Bitcoin Security and Performance with Strong Consistency via Collective Signing. In USENIX Security Symposium, 2016.
• Ewa Syta, Iulia Tamas, Dylan Visher, David Isaac Wolinsky, Philipp Jovanovic, Linus Gasser, Nicolas Gailly, Ismail Khoffi, Bryan Ford. Keeping Authorities “Honest or Bust” with Decentralized Witness Cosigning. In IEEE S&P, 2016.