We explore combining batch order-fair atomic broadcast (of-ABC) and frequent batch auction (FBA) as a defense against general order manipulations in blockchain-based decentralized exchanges (DEX). To justify FBA, we compare the welfare loss of decentralized exchanges under two market designs: continuous limit order book (CLOB), where transactions are processed sequentially, and FBA, where transactions are arranged into batches and a uniform price double auction decides execution order. We model three types of players, common investors, privately informed traders, and arbitrageurs who can provide liquidity and front-run, along with a decentralized exchange. Assuming that the exchange is realized over an of-ABC protocol, we find that FBA can achieve better social welfare compared to CLOB when (1) public information affecting the fundamental value of an asset is revealed more frequently, or (2) the block generation interval is sufficiently large, or (3) the priority fees are small compared to the asset price changes, or (4) fewer privately informed parties exist. Intrinsic reasons are that first, blockchains already treat time as discrete and ensuring order fairness there is non-trivial, allowing even more room for latency arbitrage rents under CLOB; second, sufficiently large block creation interval allows for information dispersion; third, higher priority fees discourage front-running under CLOB; additionally, FBA prioritizes price in deciding execution order and fewer informed traders mean less adverse price impact.

翻译：我们探讨将批量排序公平原子广播（of-ABC）与频繁批量拍卖（FBA）相结合，作为抵御基于区块链的去中心化交易所（DEX）中一般性订单操纵的防御手段。为论证FBA的合理性，我们比较了两种市场设计下去中心化交易所的福利损失：连续限价订单簿（CLOB，交易按顺序处理）和FBA（交易被分组为批次，通过统一价格双向拍卖决定执行顺序）。我们构建了包含三类参与者（普通投资者、知情交易者以及可提供流动性并进行抢先交易的套利者）与去中心化交易所的模型。假设交易所基于of-ABC协议实现，我们发现在以下条件下FBA相较于CLOB能实现更优的社会福利：（1）影响资产内在价值的公开信息更频繁地披露；（2）区块生成间隔足够大；（3）优先费用相对于资产价格变化较小；（4）知情参与者数量较少。内在原因在于：首先，区块链已将时间视为离散，且保证排序公平性具有非平凡复杂度，这使CLOB下延迟套利空间更大；其次，足够大的区块生成间隔有利于信息分散；第三，较高的优先费用抑制了CLOB中的抢先交易；此外，FBA在执行顺序决策中优先考虑价格，而知情交易者减少意味着更小的逆向价格冲击。