中文摘要
中本聪（Satoshi Nakamoto, 2008）发明了一种不需要政府或法治支持的新型经济系统。信任与安全转而源自密码学与经济激励的结合，且全部发生在一个完全匿名、去中心化的系统之中。本文表明，中本聪这种新颖的信任形式虽然无可否认地精巧，但在经济上存在深刻的局限性。核心论点由三个方程构成：关于诚实区块链“信任支持”（工作量、权益等）数量的零利润条件，以及关于系统抵御多数攻击（所有无许可共识形式的阿喀琉斯之踵）安全性的激励相容条件，二者共同意味着一个均衡约束——即区块链信任的“流量”成本在任何时候都必须相对于攻击该系统的收益而言足够大。相对于传统信任形式而言，这极其昂贵，并且随攻击价值线性扩展。在代表中本聪信任成为全球金融体系中更重要组成部分的情景中，信任成本将超过全球 GDP。如果攻击者除支付攻击的流量成本外，还会损失其资本的存量价值，中本聪信任将变得更具吸引力；但这要么需要系统崩溃（这很难令人安心），要么需要来自法治的外部支持。中本聪信任与植根于法治及声誉、关系、抵押品等互补来源的传统信任之间的关键区别在于规模经济：社会或企业支付固定成本，即可在大量经济活动中以低或零边际成本享有信任。
Abstract
Abstract Satoshi Nakamoto (2008) invented a new kind of economic system that does not need the support of government or rule of law. Trust and security instead arise from a combination of cryptography and economic incentives, all in a completely anonymous and decentralized system. This article shows that Nakamoto’s novel form of trust, while undeniably ingenious, is deeply economically limited. The core argument is three equations. A zero-profit condition on the quantity of honest blockchain “trust support” (work, stake, etc.) and an incentive-compatibility condition on the system’s security against majority attack (the Achilles heel of all forms of permissionless consensus) together imply an equilibrium constraint, which says that the “flow” cost of blockchain trust has to be large at all times relative to the benefits of attacking the system. This is extremely expensive relative to traditional forms of trust and scales linearly with the value of attack. In scenarios that represent Nakamoto trust becoming a more significant part of the global financial system, the cost of trust would exceed global GDP. Nakamoto trust would become more attractive if an attacker lost the stock value of their capital in addition to paying the flow cost of attack, but this requires either collapse of the system (hardly reassuring) or external support from rule of law. The key difference between Nakamoto trust and traditional trust grounded in rule of law and complementary sources, such as reputations, relationships, and collateral, is economies of scale: society or a firm pays a fixed cost to enjoy trust over a large quantity of economic activity at low or zero marginal cost.