Blockchain systems rely on oracles to bridge external information to the decentralized applications residing in the systems. Astraea protocols are decentralized oracle designs utilizing majority-voting mechanism to determine the oracle outcomes and/or rewards to voters. However, the voters are indifferent between voting through a single or multiple identities, as the potential rewards by the decentralized oracles grow linearly with the voters stakes. Additionally, the majority-voting mechanism may facilitate herd behaviors among the voters, as the voters are rewarded only if they are in agreement with the majority outcomes. In this paper, a novel oracle protocol is introduced by proposing a peer prediction-based scoring scheme along with non-linear staking rules, aiming at extracting subjective data truthfully. Specifically, an incentive compatible scoring scheme is designed so that voters uniquely maximize their expected score by honest reporting. The voters are rewarded when their report achieves a relatively high score compared to the rest of the voters, as opposed to the existing schemes, where a reward is only given when they agree to the majority. Furthermore, a non-linear stake scaling rule is proposed to discourage Sybil attacks. Detailed simulation results are presented to show the operation of the proposed oracle protocol and its improvement compared to indicative mechanisms proposed in the existing literature.

中文翻译：

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真实的去中心化区块链预言机

区块链系统依靠预言机将外部信息连接到系统中的去中心化应用程序。阿斯特拉协议是去中心化的预言机设计，利用多数投票机制来确定预言机的结果和/或对选民的奖励。然而，选民在通过单一身份或多个身份投票之间无动于衷，因为去中心化预言机的潜在回报随着选民的股份呈线性增长。此外，多数投票机制可能会促进选民之间的从众行为，因为选民只有在与多数结果一致时才会获得奖励。在本文中，通过提出基于对等预测的评分方案以及非线性赌注规则，引入了一种新颖的预言机协议，旨在真实地提取主观数据。具体来说，设计了一个激励兼容的评分方案，以便选民通过诚实的报告独特地最大化他们的预期分数。与其他选民相比，当他们的报告获得相对较高的分数时，选民将获得奖励，而现有计划仅在他们同意多数意见时才给予奖励。此外，提出了一种非线性权益缩放规则来阻止 Sybil 攻击。详细的模拟结果展示了所提出的预言机协议的操作及其与现有文献中提出的指示性机制相比的改进。