Document Open Access Logo

Byzantine Agreement and SMR with Sub-Quadratic Message Complexity (Invited Talk)

Author Idit Keidar



PDF
Thumbnail PDF

File

LIPIcs.OPODIS.2020.2.pdf
  • Filesize: 217 kB
  • 1 pages

Document Identifiers

Author Details

Idit Keidar
  • Technion, Haifa, Israel

Cite AsGet BibTex

Idit Keidar. Byzantine Agreement and SMR with Sub-Quadratic Message Complexity (Invited Talk). In 24th International Conference on Principles of Distributed Systems (OPODIS 2020). Leibniz International Proceedings in Informatics (LIPIcs), Volume 184, p. 2:1, Schloss Dagstuhl - Leibniz-Zentrum für Informatik (2021)
https://doi.org/10.4230/LIPIcs.OPODIS.2020.2

Abstract

Byzantine Agreement (BA) has been studied for four decades by now, but until recently, has been considered at a fairly small scale. In recent years, however, we begin to see practical use-cases of BA in large-scale systems, which motivates a push for reduced communication complexity. Dolev and Reischuk’s well-known lower bound stipulates that any deterministic algorithm requires Ω(n²) communication in the worst-case, and until fairly recently, almost all randomized algorithms have had at least quadratic complexity as well. This talk will present two new algorithms breaking this barrier. The first part of the talk will consider a fully asynchronous setting, focusing on randomized BA whose safety and liveness guarantees hold with high probability. It will present the first asynchronous Byzantine Agreement algorithm with sub-quadratic communication complexity. This algorithm exploits VRF-based committee sampling, which it adapts for the asynchronous model. The second part of the talk will consider the eventually synchronous model, where BA and State Machine Replication (SMR) can be solved with deterministic safety and liveness guarantees. In this context, randomization is used in order to reduce the expected communication complexity. The talk will present an algorithm for round synchronization, which is a building block for BA and SMR and constitutes the main performance bottleneck therein. It will present an algorithm that, for the first time, achieves round synchronization with expected linear message complexity and expected constant latency. Existing protocols can use this round synchronization algorithm to solve Byzantine SMR with the same asymptotic performance. The first part of the talk is based on joint work with Shir Cohen and Alexander Spiegelman, and the second part of the talk is based on joint work with Oded Naor.

Subject Classification

ACM Subject Classification
  • Networks → Network algorithms
  • Computing methodologies → Distributed algorithms
Keywords
  • Distributed Computing
  • Byzantine Agreement

Metrics

  • Access Statistics
  • Total Accesses (updated on a weekly basis)
    0
    PDF Downloads

References

  1. Shir Cohen, Idit Keidar, and Alexander Spiegelman. Not a coincidence: Sub-quadratic asynchronous byzantine agreement WHP. In Hagit Attiya, editor, 34th International Symposium on Distributed Computing, DISC 2020, October 12-16, 2020, Virtual Conference, volume 179 of LIPIcs, pages 25:1-25:17. Schloss Dagstuhl - Leibniz-Zentrum für Informatik, 2020. URL: https://doi.org/10.4230/LIPIcs.DISC.2020.25.
  2. Oded Naor and Idit Keidar. Expected linear round synchronization: The missing link for linear byzantine SMR. In Hagit Attiya, editor, 34th International Symposium on Distributed Computing, DISC 2020, October 12-16, 2020, Virtual Conference, volume 179 of LIPIcs, pages 26:1-26:17. Schloss Dagstuhl - Leibniz-Zentrum für Informatik, 2020. URL: https://doi.org/10.4230/LIPIcs.DISC.2020.26.
Questions / Remarks / Feedback
X

Feedback for Dagstuhl Publishing


Thanks for your feedback!

Feedback submitted

Could not send message

Please try again later or send an E-mail