Cellular structure for a digital fiat currency

Bitcoin introduced digital money without banks. It showed that functions of the financial system could be reliably executed by decentralized networks and in doing so raised the prospect of a new financial system. Almost a decade later, Bitcoin still works despite frequent predictions of its demise but the overwhelming majority of payments still use fiat currencies and the financial system is unchanged. We propose a cellular structure in which digital fiat currency issuers and transaction validators create functionally separate ledgers, decentralized but capable of cohering into a single system for moving digital money. The primary benefit of the cellular structure is that it lowers barriers to entry for payments by using trustless intermediation within the system. The larger purpose of this structure is to create an open foundation for a decentralized financial system in which competition can thrive but which cannot be captured by private interests.