Accountable Byzantine AgreementAccountable Byzantine Agreement β’ April 28th, 2024
In this paper, we introduce Polygraph, the first accountable Byzantine consensus algorithm. If among π users π‘ < π/3 are malicious then it ensures consensus; otherwise (if π‘ β₯ π/3), it eventually detects malicious users that cause disagree- ment. Polygraph is appealing for blockchain applications as it allows them to totally order blocks in a chain whenever possible, hence avoiding forks and double spending and, oth- erwise, to punish (e.g., via slashing) at least π/3 malicious users when a fork occurs. This problem is more difficult than perhaps it first appears. One could try identifying ma- licious senders by extending classic Byzantine consensus algorithms to piggyback signed messages. We show how- ever that to achieve accountability the resulting algorithms would then need to exchange Ξ©(π Β· π2) more bits, where π is the security parameter of the signature scheme. By con- trast, Polygraph has communication complexity π(π Β· π4). Finally, we implement Polygraph in a blockchain commit
Accountable Byzantine AgreementAccountable Byzantine Agreement β’ January 18th, 2021
In this paper, we introduce Polygraph, the first accountable Byzantine consensus algorithm. If among π users π‘ < π 3 are malicious then it ensures consensus; otherwise (if π‘ π 3), it eventually detects malicious users that cause disagree- ment. Polygraph is appealing for blockchain applications as it allows them to totally order blocks in a chain whenever possible, hence avoiding forks and double spending and, oth- erwise, to punish (e.g., via slashing) at least π 3 malicious users when a fork occurs. This problem is more difficult than perhaps it first appears. One could try identifying ma- licious senders by extending classic Byzantine consensus algorithms to piggyback signed messages. We show how- ever that to achieve accountability the resulting algorithms would then need to exchange Ξ©(π π2) more bits, where π is the security parameter of the signature scheme. By con-
