Hydrozoan: Latency-Adaptive DAG Consensus under Mixed Byzantine and Crash Faults
Hydrozoan is a DAG consensus protocol that commits in two or three delays under mixed Byzantine and crash faults.
Hydrozoan is a DAG-based consensus protocol for n = 3f+c+2p+1 validators that tolerates f Byzantine and c crash faults. Leaders commit in two message delays when at most p validators are faulty and in three delays otherwise, using one DAG, no extra messages, and no view changes. Optimal-Hydrozoan tolerates one additional fast-path fault and matches a known lower bound; both protocols' safety and liveness are machine-checked in Lean 4. A geo-distributed evaluation matches Mysticeti's throughput and commits about 25% faster when the fast quorum sits in low-latency regions.