Lemonshark: Asynchronous DAG-BFT With Early Finality
This work addresses latency issues in asynchronous BFT protocols for distributed systems, offering a significant improvement but building incrementally on existing DAG-BFT designs.
The paper tackled the problem of high latency for non-leader blocks in DAG-BFT protocols by introducing Lemonshark, which allows early finalization of transactions before official commitment, resulting in a latency reduction of up to 65% compared to state-of-the-art asynchronous BFT protocols.
DAG-Rider popularized a new paradigm of DAG-BFT protocols, separating dissemination from consensus: all nodes disseminate transactions as blocks that reference previously known blocks, while consensus is reached by electing certain blocks as leaders. This design yields high throughput but confers optimal latency only to leader blocks; non-leader blocks cannot be committed independently. We present Lemonshark, an asynchronous DAG-BFT protocol that reinterprets the DAG at a transactional level and identifies conditions where commitment is sufficient -- but not necessary -- for safe results, enabling nodes to finalize transactions before official commitment, without compromising correctness. Compared to the state-of-the-art asynchronous BFT protocol, Lemonshark reduces latency by up to 65\%.