Sybil resistance is a key requirement of decentralized consensus protocols. It is achieved by introducing a scarce resource (such as computational power, monetary stake, disk space, etc.), which prevents participants from costlessly creating multiple fake identities and hijacking the protocol. Quantum states are generically uncloneable, which suggests that they may serve naturally as an unconditionally scarce resource. In particular, uncloneability underlies quantum position-based cryptography, which is unachievable classically. We design a consensus protocol that combines classical hybrid consensus protocols with quantum position verification as the Sybil resistance mechanism, providing security in the standard model, and achieving improved energy efficiency compared to hybrid protocols based on Proof-of-Work. Our protocol inherits the benefits of other hybrid protocols, namely the faster confirmation times compared to pure Proof-of-Work protocols, and resilience against the compounding wealth issue that plagues protocols based on Proof-of-Stake Sybil resistance. We additionally propose a spam prevention mechanism for our protocol in the Random Oracle model.

翻译：抗女巫攻击是去中心化共识协议的核心要求，通常通过引入稀缺资源（如算力、货币质押、存储空间等）来实现，从而阻止参与者零成本创建大量虚假身份并劫持协议。量子态具有天然的不可克隆特性，这使其可能成为一种无条件稀缺资源。特别地，不可克隆性是量子位置加密的基础——这是经典加密无法实现的功能。本文设计了一种共识协议，将经典混合共识协议与量子位置验证相结合作为抗女巫攻击机制，在标准模型中提供安全性，且相较于基于工作量证明的混合协议具有更高的能效。该协议继承了其他混合协议的优势：相比纯工作量证明协议具有更快的确认时间，并能抵御困扰基于权益证明抗女巫攻击协议的财富集中化问题。此外，我们在随机预言机模型中为该协议提出了一种垃圾信息预防机制。