Steelhead: Interleaving Partially Synchronous and Asynchronous Commit Rules on a Shared DAG
Steelhead interleaves partially synchronous and asynchronous DAG commit rules and adapts without extra messages.
Steelhead is a dual-mode consensus mechanism that applies an asynchronous commit rule every k-th DAG round and a partially synchronous rule otherwise. Validators periodically replay the committed DAG, adopt the period with the fewest expected message delays, and fall back to k=1 if output stalls, while the asynchronous rule on coin rounds preserves liveness. It sends no messages beyond DAG blocks. Instantiations with Mysticeti and Mahi-Mahi at n at least 3f+1, and BlueBottle variants at n at least 5f+1, have safety and liveness proofs including Lean 4 mechanization; simulations match the partially synchronous protocol on a healthy network and stay near the asynchronous one when that protocol stalls.
- Every k-th round uses an asynchronous rule with a post-vote common coin.
- No extra messages are sent to agree on the operating period.
- Instantiated with Mysticeti, Mahi-Mahi, and BlueBottle variants.
- Lean 4 proofs cover safety and liveness.
From the original article
1 min read at arxiv.orgDual-mode consensus protocols are fast when the network is partially synchronous and remain live under asynchrony. We introduce Steelhead, a dual-mode mechanism that composes a partially synchronous and an asynchronous commit rule over one DAG: every k-th round is decided by the asynchronous rule, whose leader a common coin reveals after the votes, and all other rounds by the partially synchronous rule.
By George Danezis · arxiv.org
A short excerpt; the article and its images belong to the publisher. Summary, key facts and assessment above are AI-written from the article and can be wrong.