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, and/or (2) the block generation interval is sufficiently large, and/or (3) the priority fees are small compared to the asset price changes, and/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：我们探讨将批量顺序公平原子广播（of-ABC）与频繁批量拍卖（FBA）相结合，作为应对基于区块链的去中心化交易所（DEX）中通用订单操纵的防御机制。为论证FBA的合理性，我们比较了两种市场设计下DEX的福利损失：连续限价订单簿（CLOB，交易按顺序处理）与FBA（交易被分组成批次，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、可提供流动性并进行抢先交易的套利者）及DEX的模型。假设交易所基于of-ABC协议实现，研究发现：当（1）影响资产内在价值的公开信息更频繁披露，（2）区块生成间隔足够大，（3）优先费用相对于资产价格变动较小，（4）知情交易者较少时，FBA相比CLOB能实现更高的社会福利。根本原因在于：首先，区块链已将时间离散化，确保顺序公平性并非易事，这为CLOB下的延迟套利租金创造了更大空间；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以价格作为执行顺序的优先依据，而较少的知情交易者意味着更小的不利价格冲击。