In May 2023, the Ethereum blockchain experienced its first inactivity leak, a mechanism designed to reinstate chain finalization amid persistent network disruptions. This mechanism aims to reduce the voting power of validators who are unreachable within the network, reallocating this power to active validators. This paper investigates the implications of the inactivity leak on safety within the Ethereum blockchain. Our theoretical analysis reveals scenarios where actions by Byzantine validators expedite the finalization of two conflicting branches, and instances where Byzantine validators reach a voting power exceeding the critical safety threshold of one-third. Additionally, we revisit the probabilistic bouncing attack, illustrating how the inactivity leak can result in a probabilistic breach of safety, potentially allowing Byzantine validators to exceed the one-third safety threshold. Our findings uncover how penalizing inactive nodes can compromise blockchain properties, particularly in the presence of Byzantine validators capable of coordinating actions.

翻译：2023年5月，以太坊区块链首次经历非活跃性泄漏——一种旨在网络持续中断时恢复链最终确定性的机制。该机制通过降低网络中无法访问的验证者的投票权重，并将这些权重重新分配给活跃验证者。本文研究了非活跃性泄漏对以太坊区块链安全性的影响。理论分析揭示了拜占庭验证者的行为可能加速两个冲突分叉的最终确定性，以及拜占庭验证者投票权重可能超过三分之一关键安全阈值的场景。此外，我们重新审视了概率性弹跳攻击，论证非活跃性泄漏如何导致安全性的概率性破坏，可能使拜占庭验证者突破三分之一安全阈值。研究结果表明，惩罚非活跃节点的机制可能损害区块链特性，特别是在存在可协同行动的拜占庭验证者时。