Most public blockchain protocols, including the popular Bitcoin and Ethereum blockchains, do not formally specify the order in which miners should select transactions from the pool of pending (or uncommitted) transactions for inclusion in the blockchain. Over the years, informal conventions or "norms" for transaction ordering have, however, emerged via the use of shared software by miners, e.g., the GetBlockTemplate (GBT) mining protocol in Bitcoin Core. Today, a widely held view is that Bitcoin miners prioritize transactions based on their offered "transaction fee-per-byte." Bitcoin users are, consequently, encouraged to increase the fees to accelerate the commitment of their transactions, particularly during periods of congestion. In this paper, we audit the Bitcoin blockchain and present statistically significant evidence of mining pools deviating from the norms to accelerate the commitment of transactions for which they have (i) a selfish or vested interest, or (ii) received dark-fee payments via opaque (non-public) side-channels. As blockchains are increasingly being used as a record-keeping substrate for a variety of decentralized (financial technology) systems, our findings call for an urgent discussion on defining neutrality norms that miners must adhere to when ordering transactions in the chains. Finally, we make our data sets and scripts publicly available.
翻译:大部分公共链条协议,包括流行的Bitcoin 和 Etheyum 条块链,没有正式规定矿工从待决(或未承诺)交易池中选择交易以纳入该链条的顺序。然而,多年来,非正式契约或交易订单“规范”是通过矿工使用共享软件产生的,例如,在Bitcoin Core的GetBlockTemplate(GBT)采矿协议(GettBlockTemplate) 。今天,人们普遍认为,Bitcoin矿工根据他们提供的“逐字交易收费”优先处理交易。 因此,Bitcoin用户被鼓励增加收费,以加快他们交易承诺,特别是在拥挤时期。我们审计Bitcoin条块或交易“规范”的“规范”在过去几年中,通过采矿业的共享软件库偏离了标准,加速他们拥有(一)私利或既得利益的交易承诺,或(二)通过不透明(非公共)侧通道收取黑费的交易。因此,Bitcoin 用户被鼓励增加费用,以加快其交易承诺,以加快其交易承诺,特别是在拥挤交易承诺,我们在确定稳定系统中,从而确定一个可获取的公开交易规则。