As cryptographic tokens and altcoins are increasingly being built to serve as utility tokens, the notion of useful work consensus protocols is becoming ever more important. With useful work consensus protocols, users get rewards after they have carried out some specific tasks useful for the network. While in some cases the proof of some utility or service can be provided, the majority of tasks are impossible to verify reliably. To deal with such cases, we design “Proof-of-Prestige” (PoP)—a reward system that can run directly on Proof-of-Stake (PoS) blockchains or as a smart contract on top of Proof-of-Work (PoW) blockchains. PoP introduces “prestige,” which is a volatile resource that, in contrast to coins, regenerates over time. Prestige can be gained by performing useful work, spent when benefiting from services, and directly translates to users minting power. Our scheme allows us to reliably reward decentralized workers while keeping the system free for the end-users. PoP is resistant against Sybil and collusion attacks and can be used with a vast range of unverifiable tasks. We build a simulator to assess the cryptoeconomic behavior of the system and deploy a full prototype of a content dissemination platform rewarding its participants. We implement the blockchain component on both Ethereum (PoW) and Cosmos (PoS), provide a mobile application, and connect it with our scheme with a negligible memory footprint. Finally, we adapt a fair exchange protocol allowing us to atomically exchange files for rewards also in scenarios where not all the parties have Internet connectivity. Our evaluation shows that even for large Ethereum traces, PoP introduces sub-millisecond computational overhead for miners in Cosmos and less than 0.013$ smart contract invocation cost for users in Ethereum.

中文翻译：

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声望证明：用于无法验证任务的有用工作奖励系统

随着加密代币和山寨币越来越多地被构建为实用代币，有用的工作共识协议的概念变得越来越重要。通过有用的工作共识协议，用户在执行了一些对网络有用的特定任务后可以获得奖励。虽然在某些情况下可以提供某些实用程序或服务的证明，但大多数任务无法可靠地验证。为了处理这种情况，我们设计了“Proof-of-Prestige”（PoP）——一种奖励系统，可以直接在 Proof-of-Stake（PoS）区块链上运行，也可以作为工作量证明之上的智能合约（ PoW）区块链。PoP 引入了“声望”，这是一种不稳定的资源，与硬币相比，它会随着时间的推移而再生。声望可以通过做有用的工作来获得，花费在从服务中受益，并直接转化为用户的铸造能力。我们的计划使我们能够可靠地奖励分散的工人，同时保持系统对最终用户免费。PoP 可以抵抗 Sybil 和合谋攻击，并且可以用于大量无法验证的任务。我们构建了一个模拟器来评估系统的加密经济行为，并部署了一个内容传播平台的完整原型，以奖励其参与者。我们在 Ethereum (PoW) 和 Cosmos (PoS) 上实现了区块链组件，提供了一个移动应用程序，并将其与我们的方案连接起来，内存占用可以忽略不计。最后，我们采用了一个公平的交换协议，允许我们在并非所有各方都具有 Internet 连接的情况下以原子方式交换文件以获得奖励。我们的评估表明，即使对于大型以太坊痕迹，