This paper presents a partially synchronous BFT consensus protocol powered by BBCA, a lightly modified Byzantine Consistent Broadcast (BCB) primitive. BBCA provides a Complete-Adopt semantic through an added probing interface to allow either aborting the broadcast by correct nodes or exclusively, adopting the message consistently in case of a potential delivery. It does not introduce any extra types of messages or additional communication costs to BCB. BBCA is harnessed into BBCA-CHAIN to make direct commits on a chained backbone of a causally ordered graph of blocks, without any additional voting blocks or artificial layering. With the help of Complete-Adopt, the additional knowledge gained from the underlying BCB completely removes the voting latency in popular DAG-based protocols. At the same time, causal ordering allows nodes to propose blocks in parallel and achieve high throughput. BBCA-CHAIN thus closes up the gap between protocols built by consistent broadcasts (e.g., Bullshark) to those without such an abstraction (e.g., PBFT/HotStuff), emphasizing their shared fundamental principles. Using a Bracha-style BCB as an example, we fully specify BBCA-CHAIN with simplicity, serving as a solid basis for high-performance replication systems (and blockchains).

翻译：本文提出一种由BBCA驱动的部分同步拜占庭容错共识协议，其中BBCA是一种经轻度修改的拜占庭一致广播原语。BBCA通过新增探测接口提供"完全-采纳"语义，允许正确节点中止广播，或在潜在交付情况下独占性地一致采纳消息。该方案未引入任何额外消息类型，也未增加BCB的通信开销。BBCA被整合至BBCA-CHAIN协议中，可直接在因果序区块图形成的链式主干上完成提交，无需任何附加投票区块或人工分层结构。借助"完全-采纳"语义，从底层BCB获取的附加知识完全消除了当前主流基于有向无环图协议中的投票延迟。同时，因果排序机制允许节点并行提议区块，实现高吞吐量。BBCA-CHAIN由此弥合了基于一致广播构建的协议（如Bullshark）与不依赖该抽象的协议（如PBFT/HotStuff）之间的鸿沟，凸显了它们共有的基本原理。以Bracha风格BCB为例，我们以简洁形式完整规范了BBCA-CHAIN协议，为构建高性能复制系统（及区块链）奠定了坚实基础。