Principles of Distributed Systems

Volume 5923 of the series Lecture Notes in Computer Science pp 300-314

Unifying Byzantine Consensus Algorithms with Weak Interactive Consistency

  • Zarko MilosevicAffiliated withEcole Polytechnique Fédérale de Lausanne (EPFL)
  • , Martin HutleAffiliated withEcole Polytechnique Fédérale de Lausanne (EPFL)
  • , André SchiperAffiliated withEcole Polytechnique Fédérale de Lausanne (EPFL)

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The paper considers the consensus problem in a partially synchronous system with Byzantine processes. In this context, the literature distinguishes authenticated Byzantine faults, where messages can be signed by the sending process (with the assumption that the signature cannot be forged by any other process), and Byzantine faults, where there is no mechanism for signatures (but the receiver of a message knows the identity of the sender). The paper proposes an abstraction called weak interactive consistency (WIC) that unifies consensus algorithms with and without signed messages. WIC can be implemented with and without signatures.

The power of WIC is illustrated on two seminal Byzantine consensus algorithms: the Castro-Liskov PBFT algorithm (no signatures) and the Martin-Alvisi FaB Paxos algorithms (signatures). WIC allows a very concise expression of these two algorithms.