Selfish & opaque transaction ordering in the Bitcoin blockchain: the case for chain neutrality
Selfish & opaque transaction ordering in the Bitcoin blockchain: the case for chain neutrality
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DOI：
10.1145/3487552.3487823
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发表时间：
2021-10
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影响因子：
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通讯作者：
Johnnatan Messias;Mohamed Alzayat;B. Chandrasekaran;K. Gummadi;P. Loiseau;A. Mislove
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文献类型：
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作者：
Johnnatan Messias;Mohamed Alzayat;B. Chandrasekaran;K. Gummadi;P. Loiseau;A. Mislove
大多数公共区块链协议，包括流行的比特币和以太坊区块链，都没有正式指定矿工从待处理（或未提交）交易池中选择交易以包含在区块链中的顺序。然而，多年来，通过矿工使用共享软件，例如比特币核心中的 GetBlockTemplate (GBT) 挖掘协议，出现了交易排序的非正式约定或“规范”。如今，一种广泛持有的观点是，比特币矿工根据他们提供的“每字节交易费”来确定交易的优先级。因此，比特币用户被鼓励增加费用以加速其交易的承诺，特别是在拥堵期间。在本文中，我们对比特币区块链进行了审计，并提供了统计上显着的证据，证明矿池偏离了规范，以加速其交易的承诺，这些交易的目的是（i）自私或既得利益，或（ii）通过不透明（非公开）的侧通道接收暗费支付。随着区块链越来越多地被用作各种去中心化（金融技术）系统的记录保存基础，我们的研究结果呼吁紧急讨论定义矿工在链上订购交易时必须遵守的中立性规范。最后，我们公开我们的数据集和脚本。
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.