Alysson Bessani's Personal Page

I'm an associate professor with habilitation at the Informatics Department of Faculdade de Ciências da Universidade de Lisboa, on Lisbon, Portugal. I'm also member of LaSIGE (Large Scale Informatics Systems Laboratory) group where I'm involved in several research projects with the Navigators team. I've spent the Summer of 2014 at Microsoft Research Cambridge, working in the Systems and Network Group. I've also spent the Spring 2010 semester on leave to Carnegie Mellon University's CyLab working in the PDL (Parallel Data Lab).

"Those who fall in love with Practice without Theory are like the seaman on a boat without a steering wheel or a compass, who is never sure where he'll land." (Leonardo da Vinci)

"Anyone can make the simple complicated. Creativity is making the complicated simple." (Charles Mingus)

New and Noteworthy

·     I'm supper happy to receive another Test-of-Time Award at IEEE/IFIP DSN'24. This time, our DSN'14 paper about the BFT-SMaRt replication library was recognized for its impact in the last 10 years.

·     Vawlt, our multi-cloud secure storage startup, obtained another pre-seed funding round from VCs. Check the details in this blocks & files article.

·     My joint work with Christian Berger and Hans P. Reiser from U. Pasau (Germany) was recognised with the Prof. C.V. Ramamoorthy Best Paper Award on SRDS'21. The paper identifies and patches a long standing liveness bug on PBFT and BFT-SMaRt (among other protocols).

·     Our work on diversity for intrusion tolerance/BFT was recognised with the Best Student Paper Award at ACM/IFIP Middleware 2019 and the Test-of-Time Award at IEEE/IFIP DSN'21.

·     I gave a keynote entitled “The Hills and Thrills of Academic Life” at Middleware'19 doctoral symposium about my experiences as a professor. The slides are available here.

·     I received an IBM Faculty Award in 2017 to work on the Hyperledger Fabric blockchain project. A key objectives of the collaboration is to integrate BFT-SMaRt as an ordering layer for the framework. Check our paper on DSN'18 and code for Fabric 1.3.


Research Interests: Distributed Systems, Dependability, Fault Tolerance, and Security.

Selected and Recent Papers (full list, Google scholar profile)

Samaneh Shafee, Alysson Bessani, Pedro M. Ferreira. Evaluation of LLM Chatbots for OSINT-based Cyber Threat Awareness. Under submission. April 2024. Preprint on arXiv.

Christian Berger, Lívio Rodrigues, Hans P. Reiser, Vinicius Cogo, Alysson Bessani. Chasing the Speed of Light: Low-Latency Planetary-Scale Adaptive Byzantine Consensus. Under submission. May 2023. Preprint on arXiv.

Hasan Heydari, Robin Vassantlal, Alysson Bessani. Knowledge Connectivity Requirements for Solving BFT Consensus with Unknown Participants and Fault Threshold. ICDCS'24: The 44th IEEE International Conference on Distributed Computing Systems. July 2024. Extended version on arXiv. pdf

Diogo Avelãs, Hasan Heydari, Eduardo Alchieri, Tobias Distler, Alysson Bessani. Probabilistic Byzantine Fault Tolerance. PODC'24: The 43rd ACM Symposium on Principles of Distributed Computing. June 2024. Extended version on arXiv. pdf

Robin Vassantlal, Hasan Heydari, Alysson Bessani. On the Minimal Knowledge Required for Solving Stellar Consensus. ICDCS'23: The 43rd IEEE International Conference on Distributed Computing Systems. July 2023. Preprint on arXiv. pdf

Hasan Heydari, Guthemberg Silvestre, Alysson Bessani. How Hard is Asynchronous Weight Reassignment? ICDCS'23: The 43rd IEEE International Conference on Distributed Computing Systems. July 2023. Full version on arXiv. pdf

Robin Vassantlal, Eduardo Alchieri, Bernardo Ferreira, Alysson Bessani. COBRA: Dynamic Proactive Secret Sharing for Confidential BFT Services. SP'22: The 43rd IEEE Symposium on Security and Privacy. May 2022. pdf

Vinicius Cogo, Alysson Bessani. Brief Announcement: Auditable Register Emulations. Brief Announcement at DISC 2021: 35th International Symposium on Distributed Computing. September 2021. Full version on arXiv. pdf

Christian Berger, Hans P. Reiser, Alysson Bessani. Making Reads in BFT State Machine Replication Fast, Linearizable, and Live. SRDS'21: The 40th International Symposium on Reliable Distributed Systems. September 2021. Preprint on arXiv (Prof. C.V. Ramamoorthy Best Paper Award).

Fernando Alves, Aurélien Bettini, Pedro M. Ferreira, Alysson Bessani. Processing Tweets for Cybersecurity Threat Awareness. Information Systems. Vol. 95, January 2021. Preprint on arXiv. Elsevier link

Christian Berger, Hans P. Reiser, João Sousa, Alysson Bessani. AWARE: Adaptive Wide-Area Replication for Fast and Resilient Byzantine Consensus. IEEE Transactions on Dependable and Secure Systems. Accepted in October 2020. pdf IEEE link (A preliminar version was selected as one of the three best paper candidates on SRDS'19)

Fernando Alves, Ambrose Andongabo, Ilir Gashi, Pedro M Ferreira, Alysson Bessani. Follow the blue bird: A study on threat data published on Twitter. ESORICS’20: The 25th European Symposium on Research in Computer Security. September 2020. pdf

Alysson Bessani, Eduardo Alchieri, João Sousa, André Oliveira, Fernando Pedone. From Byzantine Replication to Blockchain: Consensus is only the Beginning. DSN'20: The IEEE/IFIP International Conference on Dependable Systems and Networks. July 2020. Preprint on arXiv. pdf

Enrique Fyn, Fernando Pedone, Alysson Bessani. Smart Contracts on the Move. DSN'20: The IEEE/IFIP International Conference on Dependable Systems and Networks. July 2020. Preprint on arXiv. pdf

Vinicius Cogo, João Paulo, Alysson Bessani. GenoDedup: Similarity-Based Deduplication and Delta-Encoding for Genome Sequencing Data. IEEE Transactions on Computers. Vol. 70, Num. 5. May 2020. pdf supplement IEEE link

Ricardo Macedo, João Paulo, José Pereira, Alysson Bessani. A Survey and Classification of Software-Defined Storage Systems. ACM Computing Surveys. Vol. 53, Num. 3. May 2020. preprint ACM link

Miguel Garcia, Alysson Bessani, Nuno Neves. Lazarus: Automatic Management of Diversity in BFT Systems. Middleware’19: The ACM/IFIP International Middleware Conference. Davis, USA. December 2019. pdf (best student paper award)

Ricardo Mendes, Tiago Oliveira, Vinicius Cogo, Nuno Neves, Alysson Bessani. Charon: A Secure Cloud-of-Clouds System for Storing and Sharing Big Data. IEEE Transactions on Cloud Computing. Accepted in May 2019. pdf supplement IEEE link

Wilson S. Melo Jr, Alysson Bessani, Nuno Neves, Altair Santin, Luiz F. R. C. Carmo. Using Blockchains to Implement Distributed Measuring Systems. IEEE Transactions on Instrumentation and Measurement. Vol. 68, Num. 5. March 2019. (A preliminar version appeared on I2MTC’18) pdf IEEE link

Eduardo Viegas, Altair Santin, Alysson Bessani, Nuno Neves. BigFlow: Real-time and Reliable Anomaly-based Intrusion Detection for High-Speed Networks. Future Generation Computer Systems. Vol. 93, April 2019. pdf Elsevier link

João Sousa, Alysson Bessani, Marko Vukolic. A Byzantine Fault-Tolerant Ordering Service for the Hyperledger Fabric Blockchain Platform. DSN'18: The IEEE/IFIP International Conference on Dependable Systems and Networks. June 2018. pdf (makes obsolete previous arXiv tech. report)

Miguel Garcia, Nuno Neves, Alysson Bessani. SieveQ: A Layered BFT Protection System for Critical Services. IEEE Transactions on Dependable and Secure Computing. Vol. 15, Num. 3. IEEE Computer Society. May-June 2018. preprint IEEE link

Eduardo Adilio Pelinson Alchieri, Alysson Bessani, Fabíola Greve, Joni da Silva Fraga. Knowledge Connectivity Requirements for Solving Byzantine Consensus with Unknown Participants. IEEE Transactions on Dependable and Secure Computing. Vol. 15, Num. 2. IEEE Computer Society. March-April 2018. preprint IEEE link (A preliminar version appeared on OPODIS’08).

Joel Alcântara, Tiago Oliveira, Alysson Bessani. Ginja: One-dollar Cloud-based Disaster Recovery for Databases. Middleware’17: The ACM/IFIP/USENIX International Middleware Conference. Las Vegas, USA, December 2017. pdf

Andre Nogueira, Antonio Casimiro, Alysson Bessani. Elastic State Machine Replication. IEEE Transactions on Parallel and Distributed Systems. Vol. 28, Num. 9. IEEE Computer Society. September 2017. preprint IEEE link

Tiago Oliveira, Ricardo Mendes, Alysson Bessani. Exploring Key-Value Stores in Multi-Writer Byzantine-Resilient Register Emulations. OPODIS’16: The 20th International Conference On Principles Of DIstributed Systems. Madrid, Spain, December 2016. pdf

João Sousa, Alysson Bessani. Separating the WHEAT from the Chaff: An Empirical Design for Geo-Replicated State Machines. SRDS'15: The 34th International Symposium on Reliable Distributed Systems. Montreal, Quebec, Canada. Sep. 2015. pdf

Tobias Distler, Christopher Bahn, Alysson Bessani, Frank Fischer, Flavio Junqueira. Extensible Distributed Coordination. EuroSys'15: The 10th ACM SIGOPS/EuroSys European Systems Conference. Bordeaux, France. April 2015. pdf software.

Alysson Bessani, Ricardo Mendes, Tiago Oliveira, Nuno Neves, Miguel Correia, Marcelo Pasin, Paulo Verissimo. SCFS: a Shared Cloud-backed File System. USENIX’14: USENIX Annual Technical Conference. Philadelphia, USA. June 2014. pdf.

Alysson Bessani, João Sousa, Eduardo Alchieri. State Machine Replication for the Masses with BFT-SMaRt. DSN'14: The IEEE/IFIP International Conference on Dependable Systems and Networks. Atlanta, USA. June 2014. pdf (extended version) software.

Alysson Bessani, Marcel Santos, João Felix, Nuno Neves, Miguel Correia. On the Efficiency of Durable State Machine Replication. USENIX’13: USENIX Annual Technical Conference. San Jose, CA, USA. June 2013. pdf.

Miguel Garcia, Alysson Bessani, Ilir Gashi, Nuno Neves, Rafael Obelheiro. Analysis of operating system diversity for intrusion tolerance. Software: Practice and Experience. Willey. January 2014. pdf (A preliminar version appeared on DSN’11).

Alysson Bessani, Miguel Correia, Bruno Quaresma, Fernando André, Paulo Sousa. DepSky: Dependable and Secure Storage in a Cloud-of-Clouds. ACM Transactions on Storage. Vol. 9, Num. 4. ACM. November 2013. pdf (A preliminary version appeared on EuroSys’11) software.

Giuliana Veronese, Miguel Correia, Alysson Bessani, Lau Lung, Paulo Verissimo. Efficient Byzantine Fault Tolerance. IEEE Transactions on Computers. Vol. 62, Num. 1, pp. 16-30. IEEE Computer Society. January 2013. pdf (A supplement with correctness proofs is also available).

Paulo Sousa, Alysson Neves Bessani, Miguel Correia, Nuno Ferreira Neves, Paulo Verissimo. Highly Available Intrusion-Tolerant Services with Proactive-Reactive Recovery. IEEE Transactions on Parallel and Distributed Systems. IEEE Computer Society. April 2010 (vol. 21, no. 4), pp. 452-465. pdf (A preliminary version appeared on IEEE PRDC'07).

Giuliana Santos Veronese, Miguel Correia, Alysson Neves Bessani, Lau Cheuk Lung. Spin One's Wheels? Byzantine Fault Tolerance with a Spinning Primary. SRDS'09: The 30th IEEE Symposium on Reliable Distributed Systems. Niagara Falls, USA, September 2009. pdf.

Alysson Neves Bessani, Eduardo Adilio Pelinson Alchieri, Miguel Correia, Joni da Silva Fraga. DepSpace: A Byzantine Fault-Tolerant Coordination Service. EuroSys'08: The 3rd ACM SIGOPS/EuroSys European Systems Conference. Glasgow, Scotland. April 2008. pdf.

Selected and Recent Talks

Byzantine State Machine Replication in the age of Blockchains: fundamentals and recent results (DSN 2023 tutorial, Summer'23)

From Byzantine Replication to Blockchains: Consensus is only the Beginning (FAB 2020 conference, Spring'20)

Byzantine Consensus in the Jungle (SERIAL'19 workshop at Middleware'19, Fall'19)

Adapting to Evolving Threats against BFT Systems with Weighted and Diverse Replication (BTT workshop at DISC’19, Fall’19)

Beyond Consensus in Permissioned Ledgers: Experiences in using BFT replication on DLTs (Dagstuhl seminar on blockchains and databases, Spring’19)

Beyond Consensus in Permissioned Ledgers (Hyperledger Global Forum, Fall’18)

Permissioned Ledgers: Consensus is only the Beginning (CHAIN-IN, Spring’18)

Experiences with BFT-SMaRt as a consensus substrate of Permissioned Ledgers (IFIP WG 10.4 Meeting, Spring’18)

Blockchain for Dummies (Teclabs, Spring’18)


Ongoing: SmaRtChain (FCT).

Past: VEDLIoT (EU H2020), ThreatAdapt (FCT, with SnT/University of Luxembourg), IRCoC (FCT), Abyss (FCT, with INESC-ID/IST), DiSIEM (EU H2020), SUPERCLOUD (EU H2020), SeGRID (EU FP7), BiobankCloud (EU FP7), SecFuNet (ICT EU-BR), RC-Clouds (FCT), SITAN (FCT, with UNL), TCLOUDS (EU FP7 IP), MASSIF (EU FP7 IP), ReD (FCT), ReGenesys (FCT), CloudFIT (FCT), Diverse (FCT), CRUTIAL (EU FP7 STREP), Forever (EU/RESIST NoE).

Software BFT-SMaRt (a BFT/CFT state machine replication) DepSky DepSpace

Current Students

PhD Students: Fernando Alves (Co-advised with Pedro Ferreira), Adriano Serckumecka (Co-advised with Ibéria Medeiros), Robin Vassantlal, Samaneh Shafee (Co-advised with Pedro Ferreira).

MsC Students: Tiago Antão, Miguel Carvalho, Diogo Novo.

Past Students

Vinicius Cogo (PhD 2020, FCUL), now an invited assistant professor at FCUL.

Miguel Garcia (PhD 2018, FCUL, Co-advised with Nuno Neves).

João Sousa (PhD 2017, DI-FCUL), now an associate researcher at LaSIGE, Portugal.

Luís Brandão (PhD 2015, ECE CMU/FCUL, Co-advised with Nicolas Christin), now at NIST, USA.

Eduardo Alchieri (PhD 2011, DAS UFSC-Brazil, Co-advised with Joni da Silva Fraga), now at UNB, Brazil.

Many master students... to be updated someday :-)


Informatics Engineering Distributed Systems (Fall 2007-2012, 2018, 2019), Security (Spring 2008, 2009, 2012-2, 2013), Computer Systems Architecture (Fall 2014-2016)

CMU-Portugal Masters in Information Security Intrusion Tolerance (Spring 2010, 2011)

Masters in Informatics/Informatics Engineering/Informatics Security Distributed Systems Programming (Fall 2010, 2017), Software Security (Fall 2012), Security Technologies (Spring 2013), Fault-Tolerant Distributed Systems (Fall 2014-2019, 2021-2024), Intrusion Detection and Tolerance/Intrusion Tolerance (Spring 2014-2020, 2022-2024), and Cloud Computing (Spring 2017-2018)

Information Technology Distributed Applications (Fall 2008, 2009, Spring 2015-2019), Informatics Security (2008, 2009, 2012), and Operating Systems (Fall 2021)


In my free time I enjoy a lot of things such as running, war-games, video-games, and reading.

Last Updated at June 12, 2024.