In Blockchain networks involving multiple applications, the quality of service of an application is affected by the transaction ordering. For instance, upon issuing payment transactions, users of an application would like to be notified quickly on the transactions approval. The application can be a financial institution (such as a bank), sharing the blockchain with other such applications and is represented by a node. A node might attempt to prioritize its own transactions by including them early in blocks added to the blockchain. A fair block proposal of a node follows a random selection of the transactions among the set of pending transactions the node is aware of. On the contrary, a dishonest node includes more of its transactions at the expense of transactions of other applications. In this work, we propose a toolbox of techniques to enforce such a fair block selection. First, we design an accurate statistical test for the honesty of a proposal and explain it. We conduct experiments demonstrating the accuracy of the new validation scheme. We also describe a technique that enforces fair block selection through concise commitments on the set of pending transactions known to a node. We clarify the advantages of the new mechanisms over state-of-the-art methods.

在涉及多个应用程序的区块链网络中，应用程序的服务质量受交易顺序的影响。例如，在发出支付交易时，应用程序的用户希望在交易批准时得到快速通知。应用程序可以是金融机构（如银行），与其他此类应用程序共享区块链并由节点表示。一个节点可能会尝试通过在添加到区块链的块中尽早包含它们来确定其自己的交易的优先级。一个节点的公平区块提议遵循在节点知道的一组未决交易中随机选择交易。相反，一个不诚实的节点会以牺牲其他应用程序的交易为代价来包含更多的交易。在这项工作中，我们提出了一个技术工具箱来执行这种公平的块选择。首先，我们为提案的诚实度设计了一个准确的统计测试并对其进行解释。我们进行实验来证明新验证方案的准确性。我们还描述了一种技术，该技术通过对节点已知的待处理事务集的简洁承诺来强制执行公平的块选择。我们阐明了新机制相对于最先进方法的优势。