Blockchain Consensus Protocols in the Wild (Keynote Talk)

Authors Christian Cachin, Marko Vukolic

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Christian Cachin
Marko Vukolic

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Christian Cachin and Marko Vukolic. Blockchain Consensus Protocols in the Wild (Keynote Talk). In 31st International Symposium on Distributed Computing (DISC 2017). Leibniz International Proceedings in Informatics (LIPIcs), Volume 91, pp. 1:1-1:16, Schloss Dagstuhl – Leibniz-Zentrum für Informatik (2017)


A blockchain is a distributed ledger for recording transactions, maintained by many nodes without central authority through a distributed cryptographic protocol. All nodes validate the information to be appended to the blockchain, and a consensus protocol ensures that the nodes agree on a unique order in which entries are appended. Consensus protocols for tolerating Byzantine faults have received renewed attention because they also address blockchain systems. This work discusses the process of assessing and gaining confidence in the resilience of a consensus protocols exposed to faults and adversarial nodes. We advocate to follow the established practice in cryptography and computer security, relying on public reviews, detailed models, and formal proofs; the designers of several practical systems appear to be unaware of this. Moreover, we review the consensus protocols in some prominent permissioned blockchain platforms with respect to their fault models and resilience against attacks.
  • Permissioned blockchains
  • consensus
  • Byzantine fault-tolerance
  • snake oil
  • protocol analysis


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