Cryptology and Data Security

David Lehnherr has successfully defended his Ph.D. thesis on 8 December 2025; the thesis is titled “Simplicial Structures for Epistemic Reasoning in Multi-agent Systems”. As the title reveals, this work is truly interdisciplinary and relates to logic and to distributed computing, spanning the fields between the research groups on Logic and Theory and Distributed Computing and Cryptography.

The asymmetric trust model lets each participant in a distributed system make its own trust assumptions about others, captured by an asymmetric quorum system. This contrasts with ordinary, symmetric quorum systems and threshold models, where trust assumptions are uniformly shared among participants. Fundamental problems like reliable broadcast and consensus are unsolvable in the asymmetric model …

The research paper Simplicial Belief has been accepted to the SIROCCO 2025 conference, the 32nd International Colloquium On Structural Information and Communication Complexity. SIROCCO is devoted to the study of the interplay between structural knowledge, communication, and computing in decentralized systems of multiple communicating entities.

Christian Cachin has been named one of 100 Digital Shapers 2026 by Bilanz, the biweekly Swiss business magazine. The magazine recognized him in the category of Defenders for his research on secure protocols for cryptocurrencies.

The research paper Toxic Decoys: A Path to Scaling Privacy-Preserving Cryptocurrencies has been accepted for publication in the Proceedings on Privacy Enhancing Technologies (PoPETs) and will be presented at corresponding symposium, PETS 2025, which takes place in Washington, DC, from July 14-19, 2025.

In the fall semester 2024, a seminar in the Joint Master in Computer Science at the University of Bern was offered by the CRYPTO group and focused on blockchains and cryptocurrencies.

Ulysse Pavloff has joined the CRYPTO research group in March 2026 as a postdoctoral researcher. He completed his PhD in Computer Science at Paris-Saclay University in 2024 and specializes in blockchain and game theory. Welcome!

The Cryptology and Data Security Research Group organizes a workshop on the theme of secure systems :

The research paper DAG-based Consensus with Asymmetric Trust has been accepted for presentation and publication at the PODC 2025 conference, the 44th ACM Symposium on Principles of Distributed Computing, which is held in Santa María Huatulco, Mexico, in June 2025. This work addresses the asymmetric-trust model, in which each participant is free to make its own subjective and individual trust assu…

In April 2026 Jonathan Bernhard has become a member of the CRYPTO research group as a Ph.D. student. He previously completed a M.Sc. in Computer Science at the University of Fribourg and in the Swiss Joint Master of Computer Science, where he already worked on his thesis with the group. Welcome!