Cryptocurrencies: The Network vs. The Chain

Abstract

This paper studies whether fast-settlement payment layers can replace secure baselayer blockchains in a search-theoretic monetary model. The Chain provides secure but costly and probabilistic settlement, while the Network provides instant, cost-free payments but exposes users to cyberattacks and requires sellers to incur adoption costs. In the Chain-only benchmark, buyers choose settlement intensity after bargaining. Because they do not internalize the full trade surplus, settlement intensity is inefficiently low, reducing trade efficiency and weakening the monetary value of tokens. Introducing the Network generates multiple payment equilibria. Under exogenous cyberattack risk, Chain and Network payments may coexist: the Network provides fast settlement and fallback liquidity when Chain settlement fails, while the Chain remains valuable for its security and universal acceptance. If cyberattack risk is sufficiently low, pure Network payments can arise, although pure Chain payments may also persist because Network acceptance is costly for sellers. When cyberattack risk is endogenous, broader Network adoption increases exposed balances and strengthens hackers’ incentives. This security externality weakens the Network’s value as fallback liquidity and eliminates the pure Network-payment equilibrium. The Chain, therefore, survives as a secure settlement anchor. The welfare analysis shows that Network adoption is not always welfare improving: its payment-efficiency gains must outweigh seller adoption costs and, under endogenous attacks, the resource costs of hacking. Fast-settlement layers can improve payment efficiency, but they do not generically replace secure base-layer settlement.