While Ethereum has successfully achieved dynamic availability together with safety, a fundamental delay remains between transaction execution and immutable finality. In Ethereum's current Gasper protocol, this latency is on the order of 15 minutes, exposing the network to ex ante reorganization attacks, enabling MEV extraction, and limiting the efficiency of economic settlement. These limitations have motivated a growing body of work on Speedy Secure Finality (SSF), which aims to minimize confirmation latency without weakening formal security guarantees. This paper surveys the state of the art in fast finality protocol design. We introduce the core theoretical primitives underlying this space, including reorganization resilience and the generalized sleepy model, and trace their development from Goldfish to RLMD-GHOST. We then analyze the communication and aggregation bottlenecks faced by single-slot finality protocols in large validator settings. Finally, we survey the 3-slot finality (3SF) protocol as a practical synthesis that balances fast finality with the engineering constraints of the Ethereum network.

翻译：尽管以太坊已成功实现动态可用性与安全性并存，但在交易执行与不可变终局性之间仍存在固有延迟。在以太坊当前的Gasper协议中，该延迟约为15分钟，这使网络面临事前重组攻击风险，助长MEV提取行为，并限制经济结算效率。这些局限催生了日益增长的快速安全终局性研究领域，其目标是在不削弱形式化安全保证的前提下最小化确认延迟。本文系统梳理了快速终局性协议设计的前沿进展。我们首先阐释该领域的核心理论原语，包括重组弹性与广义休眠模型，并追溯其从Goldfish到RLMD-GHOST的发展脉络。继而分析大规模验证者场景下单时隙终局性协议面临的通信与聚合瓶颈。最后，我们评述3时隙终局性协议作为兼顾快速终局性与以太坊网络工程约束的实践性解决方案。