Stellar Consensus by Instantiation

Authors Giuliano Losa, Eli Gafni, David Mazières

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Author Details

Giuliano Losa
  • Galois, Inc., Portland, OR, USA
Eli Gafni
  • UCLA, Los Angeles, CA, USA
David Mazières
  • Stanford University, CA, USA


The authors are in debt to an anonymous reviewer who suspected that our algorithm had a flaw. Indeed, that suspicion was correct.

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Giuliano Losa, Eli Gafni, and David Mazières. Stellar Consensus by Instantiation. In 33rd International Symposium on Distributed Computing (DISC 2019). Leibniz International Proceedings in Informatics (LIPIcs), Volume 146, pp. 27:1-27:15, Schloss Dagstuhl – Leibniz-Zentrum für Informatik (2019)


Stellar introduced a new type of quorum system called a Federated Byzantine Agreement System. A major difference between this novel type of quorum system and a threshold quorum system is that each participant has its own, personal notion of a quorum. Thus, unlike in a traditional BFT system, designed for a uniform notion of quorum, even in a time of synchrony one well-behaved participant may observe a quorum of well-behaved participants, while others may not. To tackle this new problem in a more general setting, we abstract the Stellar Network as an instance of what we call Personal Byzantine Quorum Systems. Using this notion, we streamline the theory behind the Stellar Network, removing the clutter of unnecessary details, and refute the conjecture that Stellar’s notion of intact set is optimally fault-tolerant. Most importantly, we develop a new consensus algorithm for the new setting.

Subject Classification

ACM Subject Classification
  • Theory of computation → Distributed computing models
  • Theory of computation → Distributed algorithms
  • Consensus
  • Stellar
  • Partial Synchrony
  • Byzantine Fault Tolerance


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