Paper 2019/587
Polygraph: Accountable Byzantine Agreement
Pierre Civit and Seth Gilbert and Vincent Gramoli
Abstract
In this paper, we introduce \emph{Polygraph}, the first accountable Byzantine consensus algorithm for partially synchronous systems. If among $n$ users $t<\frac{n}{3}$ are malicious then it ensures consensus, otherwise it eventually detects malicious users that cause disagreement. Polygraph is appealing for blockchain applications as it allows them, if $t<\frac{n}{3}$, to totally order blocks in a chain, hence avoiding forks and double spending and, otherwise, to punish malicious users when a fork occurs. We first show that stronger forms of the problem including a fixed time detection are impossible to solve before proving our solution. We also show that Polygraph has a bounded justification size so that each of its asynchronous rounds exchanges only $O(n^2)$ messages. Finally, we use a blockchain application to evaluate Polygraph on a geodistributed system of 80 machines and show that accountability reduces the performance of the non-accountable baseline by about a third, still committing thousands of transactions per second.
Metadata
- Available format(s)
- Category
- Cryptographic protocols
- Publication info
- Preprint. MINOR revision.
- Keywords
- accountabilityblockchainred bellyDBFT
- Contact author(s)
- vincent gramoli @ sydney edu au
- History
- 2021-01-18: last of 3 revisions
- 2019-05-30: received
- See all versions
- Short URL
- https://ia.cr/2019/587
- License
-
CC BY