Motivated by proof-of-stake (PoS) blockchains such as Ethereum, two key desiderata have recently been studied for Byzantine-fault tolerant (BFT) state-machine replication (SMR) consensus protocols: Finality means that the protocol retains consistency, as long as less than a certain fraction of validators are malicious, even in partially-synchronous environments that allow for temporary violations of assumed network delay bounds. Accountable safety means that in any case of inconsistency, a certain fraction of validators can be identified to have provably violated the protocol. Earlier works have developed impossibility results and protocol constructions for these properties separately. We show that accountable safety implies finality, thereby unifying earlier results.

翻译：受以太坊等权益证明（PoS）区块链的启发，拜占庭容错（BFT）状态机复制（SMR）共识协议近期研究了两个关键目标：终结性意味着，即使允许暂时违反假设网络延迟边界的部分同步环境中，只要恶意验证者比例低于特定阈值，协议就能保持一致性。可问责安全性则指，在任何不一致的情况下，能够识别出一定比例的验证者已可证明地违反了协议。此前的研究已分别针对这些属性给出了不可能性结果与协议构造。我们证明可问责安全性蕴含终结性，从而统一了此前的研究成果。