📝 SummarXiv

Abstract

Consider people with smartphones operating without external authorities or global resources other than the network itself. In this setting, high-end applications supporting sovereign democratic digital communities, community banks, and digital cooperatives require consensus executed by community members, which must be reconfigurable to support community dynamics. The Constitutional Consensus protocol aims to address this need by introducing constitutional self-governance to consensus: participants dynamically amend the participant set, supermajority threshold, and timeout parameter through the consensus protocol itself. We achieve this by enhancing a DAG-based protocol (like Cordial Miners) with participant-controlled reconfiguration, while also supporting both high- and low-throughput operation (like Morpheus), remaining quiescent when idle. This three-way synthesis uniquely combines: (1) constitutional amendments for self-governance, (2) a cryptographic DAG structure for simplicity, parallelism, and throughput, and (3) both high- and low-throughput operation. The protocol achieves consensus in $3\delta$, maintains O(n) amortized communication complexity during high throughput, and seamlessly transitions between modes. The basic protocol (without constitutional amendments) realizes these features in 25 lines of pseudocode, making it one of the most concise consensus protocols for eventual synchrony.