Distributed Systems

News

  • ROBUST Workshop 2026 in Erlangen - On October 7–8, 2026, the workshop ROBUST 2026 – Resilient Operations: Byzantine Fault Tolerance and State-Machine Replication took place at the Faculty of Engineering of…
  • Attending EuroSys 2026 in Edinburgh - From 27 April 2026 to 30 April 2026, the EuroSys conference, together with numerous workshops, took place in Edinburgh. This year, our chair was represented…
  • Laura Lawniczak’s Doctoral Defense - On February 16, Laura Lawniczak successfully defended her dissertation titled "Practical State-Machine Replication for Small-Scale Systems" (Praxisnahe Ansätze für Zustandsmaschinenreplikation in kleinskaligen Systemen). In addition…
  • Participation in the DARE 2025 Summer School - During the week of September 8–12, our employees Harald Böhm and Paul Bergmann took part in the 3rd ACM Europe Summer School on Distributed and…

Topics

Distributed systems are characterized by consisting of multiple, largely independent components that are connected via a network and jointly provide a common service. Depending on the specific form, this may range from the redundant storage of small files on just a few machines to the massively parallel processing of large amounts of data in globe-spanning cloud applications. On the one hand, the distributed nature of a system opens up new opportunities, such as improved fault tolerance through the replication of data or computations; on the other hand, it brings additional challenges, for example providing services efficiently when they are distributed across multiple geographic locations. The goal of the chair's research activities is to develop concepts and techniques that enable systems to exploit the opportunities offered by distribution while using the available resources as efficiently as possible. Our research focuses in particular on the following areas:
  • Byzantine fault tolerance, state machine replication, and consensus algorithms
  • Performance evaluation through network simulation and fault injection
  • Automated diversification, implementation, and verification of distributed systems
  • Blockchain systems, distributed ledger technology, and decentralized finance (DeFi)

Projects

BALu: Blockchain applications in aviation

Term: 1. September 2022 - 31. August 2024
Funding source: Bundesministerium für Wirtschaft und Energie (BMWE)
Acronym: BALu
Project leader:

Prof. Dr.-Ing. Rüdiger Kapitza

Das Konzept von Distributed Ledger Systemen (Blockchain) ist eine grundlegend neue Basistechnologie, welche in der öffentlichen Wahrnehmung derzeit verstärkt im Fokus steht und welche erhöhtes Potential zur Lösung von Problemstellungen in einer Vielzahl von Anwendungsbereichen verspricht.Daneben wandelt sich die Luftverkehrslandschaft absehbar mit einer massiven Zunahme an Luftverkehrsteilnehmern und weiteren Luftverkehrsarten wie autonomen Kleinstsystemen. Des Weiteren besteht ein Bedarf bei de…

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BFT2Chain: Design and validation of scalable, Byzantine fault tolerant consensus algorithms for blockchains

Term: 1. September 2022 - 30. September 2026
Funding source: Deutsche Forschungsgemeinschaft (DFG)
Acronym: BFT2Chain
Project leader:

Prof. Dr.-Ing. Rüdiger Kapitza

Distributed Ledger Technologies (DLTs), often referred to as blockchains, enable the realisation of reliable and attack-resilient services without a central infrastructure. However, the widely used proof-of-work mechanisms for DLTs suffer from high latencies of operations and enormous energy costs. Byzantine fault-tolerant (BFT) consensus protocols prove to be a potentially energy-efficient alternative to proof-of-work. However, current BFT protocols also present challenges that still limit thei…

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NEMESIS: A Novel Evaluation Platform for Measuring Endurance of Byzantine Fault-Tolerant Systems under Injected Stressors

Term: 1. January 2027 - 31. December 2029
Funding source: DFG-Einzelförderung / Sachbeihilfe (EIN-SBH)
Acronym: NEMESIS
Project leader: ,

Dr. Christian Berger

Prof. Dr.-Ing. Rüdiger Kapitza

Byzantine fault-tolerant (BFT) consensus protocols nowadays form the backbone of Distributed Ledger Technology (DLT) systems. A new generation of BFT protocols organises blocks in a directed acyclic graph instead of a linear chain, thereby achieving substantially higher throughput and better scalability. These protocols already secure considerable economic value in production DLTs. However, their attack surface and their robustness under realistic conditions remain insufficiently explored.Existi…

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Contact Persons

Dr. Christian Berger

Prof. Dr.-Ing. Rüdiger Kapitza

Research Staff

Paul Franke-Bergmann, M. Sc.

Arne Vogel, M. Sc.

Research Assistants

Moritz Reinel

Publications

2026

Preprint
Pangolin: Efficient DAG-based BFT State-Machine Replication with TEE-Accelerated Commitment
Paul Franke-Bergmann, Maya Kuhlmann, Alexander Heß, Marc Leinweber, Rüdiger Kapitza, Hannes Hartenstein, Franz J. Hauck, Christian Berger.
2026.
[arXiv] [BibTeX]
OPODIS Conference CORE B
Seamless Reconfiguration for DAG-BFT
Michael Yiqing Hu, Leander Jehl, Paul Franke-Bergmann, Jialin Li, Christian Berger.
To appear in: Proceedings of the 30th International Conference on Principles of Distributed Systems (OPODIS 2026). 2026.
[arXiv] [BibTeX]
LADC Conference Best Paper Award Nominee
Exploring Adaptive Byzantine Quorum Systems to Improve Latency in the WAN
Linus Gnan, Rüdiger Kapitza, Christian Berger.
To appear in: Proceedings of the 15th Latin-American Symposium on Dependable and Secure Computing (LADC 2026). 2026.
[arXiv] [BibTeX]
Preprint
PatchyBFT: Automating Diversification of Fault-Tolerant Systems using LLMs
Arne Vogel, Christian Berger, Rüdiger Kapitza.
2026.
[arXiv] [BibTeX]
IEEE TC Article CORE A*
Vivisecting the Dissection: On the Role of Trusted Components in BFT Protocols
Alysson Bessani, Miguel Correia, Tobias Distler, Rüdiger Kapitza, Paulo Esteves-Veríssimo, Jiangshan Yu.
In: IEEE Transactions on Computers. 2026.
[DOI] [arXiv] [BibTeX]
EuroSys Conference CORE A
OptiLog: Assigning Roles in Byzantine Consensus
Hanish Gogada, Christian Berger, Leander Jehl, Hans P. Reiser, Hein Meling.
In: Proceedings of the 21st European Conference on Computer Systems (EuroSys '26). 2026.
[DOI] [BibTeX]
PaPoC Talk
Towards practical DAG-based BFT SMR
Paul Franke-Bergmann.
In: Talk at the 13th Workshop on Principles and Practice of Consistency for Distributed Data (PaPoC '26). 2026.
[BibTeX]

2025

DARE Poster Best Poster Award
BFTeam: Towards Practical Intermittent Byzantine Fault Tolerance
Harald Böhm.
In: Poster at the 3rd ACM Europe Summer School on Distributed and Replicated Environments (DARE '25). 2025.
[BibTeX]
ROBUST Workshop
Towards a Blockchain-based Data Recorder for Small Drones
Harald Böhm, Tobias Distler, Rüdiger Kapitza.
In: 2nd Workshop on Resilient Operations – Byzantine Fault Tolerance and State-Machine Replication (ROBUST '25). 2025.
[BibTeX]
SRDS Conference CORE B
Hard Shell, Reliable Core: Improving Resilience in Replicated Systems with Selective Hybridization
Laura Lawniczak, Tobias Distler.
In: Proceedings of the 44th International Symposium on Reliable Distributed Systems (SRDS '25). 2025.
[DOI] [PDF] [BibTeX]
ARES Conference Best Paper Award Nominee CORE B
TEE-Assisted Recovery and Upgrades for Long-Running BFT Services
Ines Messadi, Markus Elias Gerber, Tobias Distler, Rüdiger Kapitza.
In: Proceedings of the 20th International Conference on Availability, Reliability and Security (ARES '25). 2025.
[DOI] [PDF] [BibTeX]

2024

PODC Conference SIGACT Research Highlights Nominee CORE A*
Probabilistic Byzantine Fault Tolerance
Diogo Avelãs, Hasan Heydari, Eduardo Alchieri, Tobias Distler, Alysson Bessani.
In: Proceedings of the 43rd Symposium on Principles of Distributed Computing (PODC 2024). 2024.
[DOI] [BibTeX]
ROBUST Workshop
Memory-Efficient Byzantine Fault-Tolerant Replication for Highly Resource-Constrained Systems
Harald Böhm, Tobias Distler.
In: 1st Workshop on Resilient Operations – Byzantine Fault Tolerance and State-Machine Replication (ROBUST '24). 2024.
[BibTeX]
RTAS Conference CORE A
TinyBFT: Byzantine Fault-Tolerant Replication for Highly Resource-Constrained Embedded Systems
Harald Böhm, Tobias Distler, Peter Wägemann.
In: Proceedings of the 30th IEEE Real-Time and Embedded Technology and Applications Symposium (RTAS 2024). 2024.
[DOI] [PDF] [BibTeX]
Thesis
Geo-Replicated Byzantine Fault-Tolerant State-Machine Replication with Low Latency
Michael Eischer.
In: Friedrich-Alexander-Universität Erlangen-Nürnberg. 2024.
[DOI] [BibTeX]
Preprint
Spider: A BFT Architecture for Geo-Replicated Cloud Services
Michael Eischer, Tobias Distler.
2024.
[arXiv] [BibTeX]
ROBUST Workshop
Tough on the Outside, Reliable on the Inside: Utilizing System Composition for Improved Resilience
Laura Lawniczak, Tobias Distler.
In: 1st Workshop on Resilient Operations – Byzantine Fault Tolerance and State-Machine Replication (ROBUST '24). 2024.
[BibTeX]
Middleware Conference CORE A
Targeting Tail Latency in Replicated Systems with Proactive Rejection
Laura Lawniczak, Tobias Distler.
In: Proceedings of the 25th Middleware Conference (Middleware '24). 2024.
[DOI] [PDF] [BibTeX]

2023

ICBC Conference CORE C
SoK: Scalability Techniques for BFT Consensus
Christian Berger, Signe Schwarz-Rüsch, Arne Vogel, Kai Bleeke, Leander Jehl, Hans P. Reiser, Rüdiger Kapitza.
In: Proceedings of the 5th IEEE International Conference on Blockchain and Cryptocurrency. 2023.
[DOI] [arXiv] [BibTeX]
DSN Conference CORE A
Micro Replication
Tobias Distler, Michael Eischer, Laura Lawniczak.
In: Proceedings of the 53rd Annual IEEE/IFIP International Conference on Dependable Systems and Networks (DSN '23). 2023.
[DOI] [BibTeX]
PaPoC Workshop
Generic Checkpointing Support for Stream-based State-Machine Replication
Laura Lawniczak, Marco Ammon, Tobias Distler.
In: Proceedings of the 10th Workshop on Principles and Practice of Consistency for Distributed Data (PaPoC '23). 2023.
[DOI] [PDF] [BibTeX]

2022

Middleware Conference CORE A
SplitBFT: Improving Byzantine Fault Tolerance Safety Using Trusted Compartments
Ines Messadi, Markus Horst Becker, Kai Bleeke, Leander Jehl, Sonia Ben Mokhtar, Rüdiger Kapitza.
In: Middleware 2022 - Proceedings of the 23rd ACM/IFIP International Middleware Conference. 2022.
[DOI] [BibTeX]
Middleware Conference CORE A
EventChain: A Blockchain Framework for Secure, Privacy-Preserving Event Verification
Signe Schwarz-Rüsch, Michael Behlendorf, Markus Horst Becker, René Kudlek, Hesham Hosney Elsayed Mohamed, Felix Schoenitz, Leander Jehl, Rüdiger Kapitza.
In: 23rd ACM/IFIP International Middleware Conference. 2022.
[DOI] [BibTeX]
DSN Conference CORE A
ZugChain: Blockchain-Based Juridical Data Recording in Railway Systems
Signe Schwarz-Rüsch, Kai Bleeke, Ines Messadi, Stefan Schmidt, Andreas Krampf, Katharina Olze, Susanne Stahnke, Robert Schmid, Lukas Pirl, Roland Kittel, Andreas Polze, Marquart Franz, Matthias Müller, Leander Jehl, Rüdiger Kapitza.
In: Proceedings of the 52nd International Conference on Dependable Systems and Networks. 2022.
[DOI] [PDF] [BibTeX]

2021

ACM CSUR Article CORE A*
Byzantine Fault-Tolerant State-machine Replication from a Systems Perspective
Tobias Distler.
In: ACM Computing Surveys 54. 2021.
[DOI] [BibTeX]
PRDC Conference CORE B
Egalitarian Byzantine Fault Tolerance
Michael Eischer, Tobias Distler.
In: 2021 IEEE 26th Pacific Rim International Symposium on Dependable Computing (PRDC). 2021.
[DOI] [PDF] [BibTeX]
EDCC Conference
Stream-based State Machine Replication
Laura Lawniczak, Tobias Distler.
In: Proceedings of the 17th European Dependable Computing Conference (EDCC '21). 2021.
[DOI] [arXiv] [BibTeX]

2020

Talk
Vision trifft auf Wirklichkeit: Ergebnisse und Erkenntnisse langjähriger Forschung im Bereich replizierter Systeme
Tobias Distler.
2020.
[PDF] [BibTeX]
Middleware Conference Best Student Paper Award CORE A
Resilient Cloud-based Replication with Low Latency
Michael Eischer, Tobias Distler.
In: Middleware 2020 - Proceedings of the 2020 21st International Middleware Conference. 2020.
[DOI] [PDF] [BibTeX]
PaPoC Workshop
Low-Latency Geo-Replicated State Machines with Guaranteed Writes
Michael Eischer, Benedikt Straßner, Tobias Distler.
In: Proceedings of the 7th Workshop on Principles and Practice of Consistency for Distributed Data, PaPoC 2020. 2020.
[DOI] [PDF] [BibTeX]

2019

PaPoC Workshop
In Search of a Scalable Raft-based Replication Architecture
Christian Deyerl, Tobias Distler.
In: Proceedings of the 6th Workshop on Principles and Practice of Consistency for Distributed Data, PaPoC 2019. 2019.
[DOI] [BibTeX]
SRDS Conference CORE A
Deterministic Fuzzy Checkpoints
Michael Eischer, Markus Büttner, Tobias Distler.
In: Proceedings of the 38th International Symposium on Reliable Distributed Systems (SRDS '19). 2019.
[DOI] [PDF] [BibTeX]

2018

DAIS Conference Best Paper Award CORE B
Strome: Energy-Aware Data-Stream Processing
Christopher Eibel, Christian Gulden, Wolfgang Schröder-Preikschat, Tobias Distler.
In: Proceedings of the 18th International Conference on Distributed Applications and Interoperable Systems (DAIS '18). 2018.
[DOI] [BibTeX]
DSN-W Workshop
Latency-Aware Leader Selection for Geo-Replicated Byzantine Fault-Tolerant Systems
Michael Eischer, Tobias Distler.
In: Proceedings of the 48th International Conference on Dependable Systems and Networks Workshops (DSN-W '18). 2018.
[DOI] [PDF] [BibTeX]
Computing Article CORE B
Scalable Byzantine Fault-tolerant State-Machine Replication on Heterogeneous Servers
Michael Eischer, Tobias Distler.
In: Computing. 2018.
[DOI] [PDF] [BibTeX]
DSN Conference CORE A
Troxy: Transparent Access to Byzantine Fault-Tolerant Systems
Bijun Li, Nico Weichbrodt, Johannes Behl, Pierre-Louis Aublin, Tobias Distler, Rüdiger Kapitza.
In: Proceedings of the 48th International Conference on Dependable Systems and Networks (DSN '18). 2018.
[DOI] [PDF] [BibTeX]

2017

Report
Hybster - A Highly Parallelizable Protocol for Hybrid Fault-Tolerant Service Replication
Johannes Behl, Tobias Distler, Rüdiger Kapitza.
2017.
[DOI] [BibTeX]
EuroSys Conference CORE A
Hybrids on Steroids: SGX-based High Performance BFT
Johannes Behl, Tobias Distler, Rüdiger Kapitza.
In: Proceedings of the 12th European Conference on Computer Systems (EuroSys '17). 2017.
[DOI] [PDF] [BibTeX]

2016

IEEE TC Article CORE A*
Resource-efficient Byzantine Fault Tolerance
Tobias Distler, Christian Cachin, Rüdiger Kapitza.
In: IEEE Transactions on Computers 65(9). 2016.
[DOI] [PDF] [BibTeX]
EDCC Conference
SAREK: Optimistic Parallel Ordering in Byzantine Fault Tolerance
Bijun Li, Wenbo Xu, Muhammad Zeeshan Abid, Tobias Distler, Rüdiger Kapitza.
In: Proceedings of the 12th European Dependable Computing Conference (EDCC '16). 2016.
[DOI] [BibTeX]

2015

Middleware Conference CORE A
Consensus-Oriented Parallelization: How to Earn Your First Million
Johannes Behl, Tobias Distler, Rüdiger Kapitza.
In: Proceedings of the 16th Middleware Conference (Middleware '15). 2015.
[DOI] [PDF] [BibTeX]
ARM Workshop
Towards Energy-Proportional State-Machine Replication
Christopher Eibel, Tobias Distler.
In: Proceedings of the 14th Workshop on Adaptive and Reflective Middleware (ARM '15). 2015.
[DOI] [PDF] [BibTeX]

2014

HotDep Workshop
Scalable BFT for Multi-Cores: Actor-based Decomposition and Consensus-oriented Parallelization
Johannes Behl, Tobias Distler, Rüdiger Kapitza.
In: Proceedings of the 10th Workshop on Hot Topics in System Dependability (HotDep '14). 2014.
[PDF] [BibTeX]

2012

EuroSys Conference CORE A
CheapBFT: Resource-efficient Byzantine Fault Tolerance
Rüdiger Kapitza, Johannes Behl, Christian Cachin, Tobias Distler, Simon Kuhnle, Seyed Vahid Mohammadi, Wolfgang Schröder-Preikschat, Klaus Stengel.
In: Proceedings of the EuroSys 2012 Conference (EuroSys '12). 2012.
[DOI] [PDF] [BibTeX]

2011

EuroSys Conference CORE A
Increasing Performance in Byzantine Fault-Tolerant Systems with On-Demand Replica Consistency
Tobias Distler, Rüdiger Kapitza.
In: Proceedings of the EuroSys 2011 Conference (EuroSys '11). 2011.
[DOI] [PDF] [BibTeX]
NDSS Conference CORE A
SPARE: Replicas on Hold
Tobias Distler, Rüdiger Kapitza, Ivan Popov, Hans Reiser, Wolfgang Schröder-Preikschat.
In: Proceedings of the 18th Network and Distributed System Security Symposium (NDSS '11). 2011.
[PDF] [BibTeX]

2010

SICHERHEIT Conference
State Transfer for Hypervisor-Based Proactive Recovery of Heterogeneous Replicated Services
Tobias Distler, Rüdiger Kapitza, Hans P. Reiser.
In: Proceedings of the 5th "Sicherheit, Schutz und Zuverlässigkeit" Conference (SICHERHEIT '10). 2010.
[PDF] [BibTeX]

2009

MAI Workshop
Functional Decomposition and Interactions in Hybrid Intrusion-tolerant Systems
Hans P. Reiser, Tobias Distler, Rüdiger Kapitza.
In: Proceedings of the 3rd Workshop on Middleware-Application Interaction (MAI '09). 2009.
[DOI] [BibTeX]

2008

Middleware Companion Workshop
FOREVER: Fault/intrusiOn REmoVal through Evolution & Recovery
Alysson Bessani, Hans P. Reiser, Paulo Sousa, Ilir Gashi, Vladimir Stankovic, Tobias Distler, Rüdiger Kapitza, Alessandro Daidone, Rafael Obelheiro.
In: Companion '08: Proceedings of the ACM/IFIP/USENIX Middleware '08 Conference Companion. 2008.
[DOI] [BibTeX]
WRAITS Workshop
Efficient State Transfer for Hypervisor-Based Proactive Recovery
Tobias Distler, Rüdiger Kapitza, Hans P. Reiser.
In: Proceedings of the 2nd Workshop on Recent Advances on Intrusion-Tolerant Systems (WRAITS '08). 2008.
[DOI] [BibTeX]