In this paper, we review the undercutting attacks in the transaction-fee-based regime of proof-of-work (PoW) blockchains with the longest chain fork-choice rule. Next, we focus on the problem of fluctuations in mining revenue and the mining gap - i.e., a situation, in which the immediate reward from transaction fees does not cover miners' expenditures. To mitigate these issues, we propose a solution that splits transaction fees from a mined block into two parts - (1) an instant reward for the miner of a block and (2) a deposit sent to one or more fee-redistribution smart contracts ($\mathcal{FRSC}$s) that are part of the consensus protocol. At the same time, these redistribution smart contracts reward the miner of a block with a certain fraction of the accumulated funds of the incoming fees over a predefined time. This setting enables us to achieve several interesting properties that are beneficial for the incentive stability and security of the protocol. With our solution, the fraction of Default-Compliant miners who strictly do not execute undercutting attacks is lowered from the state-of-the-art result of 66% to 30%.

翻译：本文研究了在基于最长链分叉规则的工作量证明（PoW）区块链中，采用交易费机制时存在的“挖矿攻击”问题。随后，我们聚焦于挖矿收益波动与“挖矿缺口”问题——即交易费即时收益无法覆盖矿工支出的情形。为缓解这些问题，我们提出了一种解决方案：将已挖出区块中的交易费拆分为两部分——(1) 矿工的即时奖励，以及(2) 发送至一个或多个作为共识协议组成部分的费用再分配智能合约（$\mathcal{FRSC}$s）的存款。同时，这些再分配智能合约会在预设时间段内，将累积新进入费用的一定比例奖励给区块矿工。该设置使我们能够实现若干对协议激励稳定性与安全性有利的有趣特性。通过我们的方案，严格不执行挖矿攻击的默认合规矿工比例，从此前最优结果的66%降低至30%。