Paper 2025/1829
On the Limits of Consensus under Dynamic Availability and Reconfiguration
, a16z Crypto Research, University of Illinois at Urbana-ChampaignAbstract
Proof-of-stake blockchains require consensus protocols that support Dynamic Availability and Reconfiguration (so-called DAR setting), where the former means that the consensus protocol should remain live even if a large number of nodes temporarily crash, and the latter means it should be possible to change the set of operating nodes over time. State-of-the-art protocols for the DAR setting, such as Ethereum, Cardano’s Ouroboros, or Snow White, require unrealistic additional assumptions, such as social consensus, or that key evolution is performed even while nodes are not participating. In this paper, we identify the necessary and sufficient adversarial condition under which consensus can be achieved in the DAR setting without additional assumptions. We then introduce a new and realistic additional assumption: honest nodes dispose of their cryptographic keys the moment they express intent to exit from the set of operating nodes. To add reconfiguration to any dynamically available consensus protocol, we provide a bootstrapping gadget that is particularly simple and efficient in the common optimistic case of few reconfigurations and no double-spending attempts.
Metadata
- Available format(s)
-
PDF
- Publication info
- Preprint.
- Contact author(s)
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jneu @ a16z com
jmnieto2 @ illinois edu
renling @ illinois edu - History
- 2025-10-08: approved
- 2025-10-04: received
- See all versions
- Short URL
- https://ia.cr/2025/1829
- License
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CC BY-NC-ND
BibTeX
@misc{cryptoeprint:2025/1829,
author = {Joachim Neu and Javier Nieto and Ling Ren},
title = {On the Limits of Consensus under Dynamic Availability and Reconfiguration},
howpublished = {Cryptology {ePrint} Archive, Paper 2025/1829},
year = {2025},
url = {https://eprint.iacr.org/2025/1829}
}
