Paper 2023/397

Extended Abstract: HotStuff-2: Optimal Two-Phase Responsive BFT

Dahlia Malkhi, Chainlink Labs
Kartik Nayak, Duke University
Abstract

In this paper, we observe that it is possible to solve partially-synchronous BFT and simultaneously achieves $O(n^2)$ worst-case communication, optimistically linear communication, a two-phase commit regime within a view, and optimistic responsiveness. Prior work falls short in achieving one or more of these properties, e.g., the most closely related work, HotStuff, requires a three-phase view while achieving all other properties. We demonstrate that these properties are achievable through a two-phase HotStuff variant named HotStuff-2. The quest for two-phase HotStuff variants that achieve all the above desirable properties has been long, producing a series of results that are yet sub-optimal and, at the same time, are based on somewhat heavy hammers. HotStuff-2 demonstrates that none of these are necessary: HotStuff-2 is remarkably simple, adding no substantive complexity to the original HotStuff protocol. The main takeaway is that two phases are enough for BFT after all.

Metadata
Available format(s)
PDF
Category
Foundations
Publication info
Preprint.
Keywords
BFTCommunication complexityOptimistic Responsiveness
Contact author(s)
dahliamalkhi @ gmail com
kartik1507 @ gmail com
History
2023-04-17: last of 5 revisions
2023-03-20: received
See all versions
Short URL
https://ia.cr/2023/397
License
No rights reserved
CC0

BibTeX

@misc{cryptoeprint:2023/397,
      author = {Dahlia Malkhi and Kartik Nayak},
      title = {Extended Abstract: HotStuff-2: Optimal Two-Phase Responsive BFT},
      howpublished = {Cryptology ePrint Archive, Paper 2023/397},
      year = {2023},
      note = {\url{https://eprint.iacr.org/2023/397}},
      url = {https://eprint.iacr.org/2023/397}
}
Note: In order to protect the privacy of readers, eprint.iacr.org does not use cookies or embedded third party content.