Synchronous Byzantine Agreement with Expected O(1) Rounds, Expected \(O(n^2)\) Communication, and Optimal Resilience

  • Ittai Abraham
  • Srinivas Devadas
  • Danny Dolev
  • Kartik Nayak
  • Ling RenEmail author
Conference paper
Part of the Lecture Notes in Computer Science book series (LNCS, volume 11598)


We present new protocols for Byzantine agreement in the synchronous and authenticated setting, tolerating the optimal number of f faults among \(n=2f+1\) parties. Our protocols achieve an expected O(1) round complexity and an expected \(O(n^2)\) communication complexity. The exact round complexity in expectation is 10 for a static adversary and 16 for a strongly rushing adaptive adversary. For comparison, previous protocols in the same setting require expected 29 rounds.



We thank Dahlia Malkhi and Benjamin Chan for many useful discussions.


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Copyright information

© International Financial Cryptography Association 2019

Authors and Affiliations

  • Ittai Abraham
    • 1
  • Srinivas Devadas
    • 2
  • Danny Dolev
    • 3
  • Kartik Nayak
    • 1
    • 4
  • Ling Ren
    • 1
    • 5
    Email author
  1. 1.VMware ResearchPalo AltoUSA
  2. 2.MITCambridgeUSA
  3. 3.Hebrew University of JerusalemJerusalemIsrael
  4. 4.Duke UniversityDurhamUSA
  5. 5.University of Illinois at Urbana-ChampaignUrbanaUSA

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