Better Safe than Sorry: Recovering after Adversarial Majority

Srivatsan Sridhar; Dionysis Zindros; David Tse

Paper 2023/1556

Better Safe than Sorry: Recovering after Adversarial Majority

Srivatsan Sridhar

, Stanford University

Dionysis Zindros, Stanford University

David Tse

, Stanford University

Abstract

The security of blockchain protocols is a combination of two properties: safety and liveness. It is well known that no blockchain protocol can provide both to sleepy (intermittently online) clients under adversarial majority. However, safety is more critical in that a single safety violation can cause users to lose money. At the same time, liveness must not be lost forever. We show that, in a synchronous network, it is possible to maintain safety for all clients even during adversarial majority, and recover liveness after honest majority is restored. Our solution takes the form of a recovery gadget that can be applied to any protocol with certificates (such as HotStuff, Streamlet, Tendermint, and their variants).

Metadata

Available format(s): PDF
Category: Cryptographic protocols
Publication info: Preprint.
Keywords: consensus blockchain
Contact author(s): svatsan @ stanford edu
dionyziz @ stanford edu
dntse @ stanford edu
History: 2023-11-03: revised; 2023-10-10: received; See all versions
Short URL: https://ia.cr/2023/1556
License: CC BY

BibTeX

@misc{cryptoeprint:2023/1556,
      author = {Srivatsan Sridhar and Dionysis Zindros and David Tse},
      title = {Better Safe than Sorry: Recovering after Adversarial Majority},
      howpublished = {Cryptology ePrint Archive, Paper 2023/1556},
      year = {2023},
      note = {\url{https://eprint.iacr.org/2023/1556}},
      url = {https://eprint.iacr.org/2023/1556}
}