Recent developments in the Byzantine Fault Tolerant consensus protocols have shown the DAG-based protocols to be a very promising technique. While early implementations of DAG-based protocols such as Narwhal/Bullshark trade high throughput for a low latency, the latest versions of DAG-based protocols such as Mysticeti and Shoal++ show that indeed a latency comparable to that of traditional consensus protocols such as HotStuff can be achieve with the DAG-based consensus protocols while still maintaining high throughput. Mysticeti in particular achieves a low latency by implementing a novel approach of using an uncertified DAG - a significant breakthrough comparing to the certified DAG used in the previous generations of the protocol. However, the uncertified DAG exposes the system to new vectors of attacks by Byzantine validators that did not exist in the certified DAG protocols. In this paper we describe those issues and present the Adelie protocol, that addresses issues that comes with an uncertified DAG. We also incorporate some of the techniques from the Shoal++ to reduce latency even further. This paper also presents an implementation of Adelie protocol - bftd that demonstrates yet another breakthrough in the maximum achieved TPS and low latency.

翻译：近年来，拜占庭容错共识协议的发展表明，基于有向无环图（DAG）的协议已成为一项极具前景的技术。早期基于DAG的协议（如Narwhal/Bullshark）以高吞吐量换取低延迟，而最新版本的基于DAG协议（如Mysticeti和Shoal++）则证明，此类协议在保持高吞吐量的同时，确实能够实现与传统共识协议（如HotStuff）相当的延迟。Mysticeti尤其通过采用一种新颖的未认证DAG方法实现了低延迟——相较于前几代协议使用的认证DAG，这是一项重大突破。然而，未认证DAG使系统面临拜占庭验证者发起的新型攻击向量，这些攻击在认证DAG协议中并不存在。本文阐述了这些问题，并提出Adelie协议以应对未认证DAG带来的挑战。我们还借鉴了Shoal++的部分技术以进一步降低延迟。本文同时介绍了Adelie协议的实现——bftd，该实现展示了在最高达成TPS与低延迟方面的又一突破。