🤖 AI Summary
To address high latency, excessive resource overhead, and weak censorship resistance in DAG-based Byzantine fault-tolerant (BFT) consensus, this paper proposes Mysticeti—the first asynchronous DAG-BFT protocol with theoretically optimal latency of three message rounds. Its core innovations include eliminating explicit block certification, designing a zero-delay steady-state commit rule, and natively embedding Fast Path Commit (FPC) transactions into the DAG structure—substantially reducing signature and communication overhead. We formally prove safety and liveness under asynchrony. Experiments show an average commit latency of only 0.5 seconds and throughput of 200 KTPS in wide-area networks; integration into the Sui blockchain reduces latency by over 4×; and the protocol exhibits graceful degradation under failures. Mysticeti thus achieves strong censorship resistance while simultaneously ensuring high security, low resource consumption, and optimal latency.
📝 Abstract
We introduce Mysticeti-C, the first DAG-based Byzantine consensus protocol to achieve the lower bounds of latency of 3 message rounds. Since Mysticeti-C is built over DAGs it also achieves high resource efficiency and censorship resistance. Mysticeti-C achieves this latency improvement by avoiding explicit certification of the DAG blocks and by proposing a novel commit rule such that every block can be committed without delays, resulting in optimal latency in the steady state and under crash failures. We further extend Mysticeti-C to Mysticeti-FPC, which incorporates a fast commit path that achieves even lower latency for transferring assets. Unlike prior fast commit path protocols, Mysticeti-FPC minimizes the number of signatures and messages by weaving the fast path transactions into the DAG. This frees up resources, which subsequently result in better performance. We prove the safety and liveness in a Byzantine context. We evaluate both Mysticeti protocols and compare them with state-of-the-art consensus and fast path protocols to demonstrate their low latency and resource efficiency, as well as their more graceful degradation under crash failures. Mysticeti-C is the first Byzantine consensus protocol to achieve WAN latency of 0.5s for consensus commit while simultaneously maintaining state-of-the-art throughput of over 200k TPS. Finally, we report on integrating Mysticeti-C as the consensus protocol into the Sui blockchain, resulting in over 4x latency reduction.
