Blockchain systems based on a reusable resource, such as proof-of-stake (PoS), provide weaker security guarantees than those based on proof-of-work. Specifically, they are vulnerable to long-range attacks, where an adversary can corrupt prior participants in order to rewrite the full history of the chain. To prevent this attack on a PoS chain, we propose a protocol that checkpoints the state of the PoS chain to a proof-of-work blockchain such as Bitcoin. Our checkpointing protocol hence does not rely on any central authority. Our work uses Schnorr signatures and leverages Bitcoin recent Taproot upgrade, allowing us to create a checkpointing transaction of constant size. We argue for the security of our protocol and present an open-source implementation that was tested on the Bitcoin testnet.

翻译：基于可重复使用的资源,例如“获取证明”(POS)的屏障链系统提供的安全保障比基于“工作证明”(POS)的安全保障弱。具体地说,这些系统容易受到长期攻击,敌人可以腐蚀先前的参与者,以便重写整个链条的历史。为了防止这种对“获取证明”的系统的攻击,我们提议了一项议定书,将“获取证明”(POS)链的状态与“获取证明”(Bitcoin)等“工作证明”的链条连接起来。因此,我们的“检查协议”并不依赖任何中央权威。我们的工作利用Schnorr的签名和利用Bitcoin最近对Taproot的升级,允许我们建立一个固定规模的检查站交易。我们主张协议的安全性,并提出在“Bitcoin”测试网上测试的开放源实施。