conference paper published yes Giorgos Tsimos author Anastasios Kichidis author Alberto Sonnino author Eleftherios Kokoris Kogias author f5983044-d7ef-11ea-ac6d-fd1430a26d30 ElKo department ICDCS: International Conference on Distributed Computing Systems Recent advancements on DAG-based consensus protocols allow for blockchains with improved metrics and properties, such as throughput and censorship-resistance. Variants of the Bullshark [18] consensus protocol are adopted for practical use by the Sui blockchain, for improved latency. However, the protocol is leader-based, and is strongly affected by crashed leaders that can lead to various performance issues, for example, decreased transaction throughput. In this paper, we propose HammerHead, a DAG-based consensus protocol, that is inspired by Carousel [8] and provides Leader-Utilization. Our proposal differs from Carousel, which is built for a chained consensus protocol; in HammerHead chain quality is inherited by the DAG. HammerHead needs to preserve safety and liveness, despite validators committing leader vertices asynchronously. The key idea is to update leader schedules dynamically, based on the validators' scores during the previous schedule. We implement HammerHead and show a minor improvement in performance for cases without faults. The major improvements in comparison to Bullshark appear in faulty settings. Specifically, we show a drastic, 2x-latency improvement and up to 40% increased throughput when crash faults occur (100 validators, 33 faults). IEEE2024Jersey City, NJ, United States eng 1063-6927 2575-8411 9798350386059 2309.12713 00130443020012010.1109/ICDCS60910.2024.00129 1377-1387 Tsimos G, Kichidis A, Sonnino A, Kokoris Kogias E. 2024. HammerHead: Leader reputation for dynamic scheduling. Proceedings - International Conference on Distributed Computing Systems. ICDCS: International Conference on Distributed Computing Systems, 1377–1387. G. Tsimos, A. Kichidis, A. Sonnino, E. Kokoris Kogias, in:, Proceedings - International Conference on Distributed Computing Systems, IEEE, 2024, pp. 1377–1387. Tsimos, Giorgos, Anastasios Kichidis, Alberto Sonnino, and Eleftherios Kokoris Kogias. “HammerHead: Leader Reputation for Dynamic Scheduling.” In <i>Proceedings - International Conference on Distributed Computing Systems</i>, 1377–87. IEEE, 2024. <a href="https://doi.org/10.1109/ICDCS60910.2024.00129">https://doi.org/10.1109/ICDCS60910.2024.00129</a>. Tsimos G, Kichidis A, Sonnino A, Kokoris Kogias E. HammerHead: Leader reputation for dynamic scheduling. In: <i>Proceedings - International Conference on Distributed Computing Systems</i>. IEEE; 2024:1377-1387. doi:<a href="https://doi.org/10.1109/ICDCS60910.2024.00129">10.1109/ICDCS60910.2024.00129</a> G. Tsimos, A. Kichidis, A. Sonnino, and E. Kokoris Kogias, “HammerHead: Leader reputation for dynamic scheduling,” in <i>Proceedings - International Conference on Distributed Computing Systems</i>, Jersey City, NJ, United States, 2024, pp. 1377–1387. Tsimos, G., Kichidis, A., Sonnino, A., &#38; Kokoris Kogias, E. (2024). HammerHead: Leader reputation for dynamic scheduling. In <i>Proceedings - International Conference on Distributed Computing Systems</i> (pp. 1377–1387). Jersey City, NJ, United States: IEEE. <a href="https://doi.org/10.1109/ICDCS60910.2024.00129">https://doi.org/10.1109/ICDCS60910.2024.00129</a> Tsimos, Giorgos, et al. “HammerHead: Leader Reputation for Dynamic Scheduling.” <i>Proceedings - International Conference on Distributed Computing Systems</i>, IEEE, 2024, pp. 1377–87, doi:<a href="https://doi.org/10.1109/ICDCS60910.2024.00129">10.1109/ICDCS60910.2024.00129</a>. 180712024-09-15T22:01:41Z2025-09-08T09:42:36Z