论文标题
EventWarden：一项分散事件驱动的代理服务，用于外包以太坊的区块链中的任意交易
EventWarden: A Decentralized Event-driven Proxy Service for Outsourcing Arbitrary Transactions in Ethereum-like Blockchains
论文作者
论文摘要
交易代表了区块链中的基本组件，因为它们是用户更改区块链状态的主要手段。当前的区块链系统（例如比特币和以太坊）要求用户不断观察感兴趣的状态变化或区块链中发生的事件，并要求用户明确释放所需的交易以响应区块链中观察到的事件。本文提出了EventWarden，这是一种分散的事件驱动的代理服务，供用户将类似以太坊的区块链交易外包。 EventWarden采用了智能合约和区块链日志的新型组合。 EventWarden允许用户创建一个代理智能合约，该合约指定了感兴趣的事件，还保留任意交易以发布。在观察处方事件的发生后，区块链网络中的任何人都可以通过向合同证明已将事件记录到区块链日志中的合同中，以赚取代理合同，以赚取合同中保留的服务费，然后自动触发代理合同以释放保留交易。我们表明，在规定的事件发生时，预留交易只能从代理合同中释放。我们还证明，只要有区块链网络中的单个成员被服务费激励在规定事件发生后拨打代理合同，就可以保证保留交易。我们通过以太坊官方测试网络实施EventWarden。结果表明，Eventwarden在实践中有效，并且可以使用。
Transactions represent a fundamental component in blockchains as they are the primary means for users to change the blockchain state. Current blockchain systems such as Bitcoin and Ethereum require users to constantly observe the state changes of interest or the events taking place in a blockchain and requires the user to explicitly release the required transactions to respond to the observed events in the blockchain. This paper proposes EventWarden, a decentralized event-driven proxy service for users to outsource transactions in Ethereum-like blockchains. EventWarden employs a novel combination of smart contracts and blockchain logs. EventWarden allows a user to create a proxy smart contract that specifies an interested event and also reserves an arbitrary transaction to release. Upon observing the occurrence of the prescribed event, anyone in the Blockchain network can call the proxy contract to earn the service fee reserved in the contract by proving to the contract that the event has been recorded into blockchain logs, which then automatically triggers the proxy contract to release the reserved transaction. We show that the reserved transaction can only get released from the proxy contract when the prescribed event has taken place. We also demonstrate that as long as a single member in the Blockchain network is incentivized by the service fee to call the proxy contract after the prescribed event has taken place, the reserved transaction is guaranteed to get released. We implement EventWarden over the Ethereum official test network. The results demonstrate that EventWarden is effective and is ready-to-use in practice.
