Bitcoin execution and trust models

This report provides a structured overview of Bitcoin programmability and the emerging ecosystem of Bitcoin-aligned execution layers. It categorizes current and proposed architectures—including sidechains, externally sequenced systems, rollups, and bridging models—based on how they interact with Bitcoin’s base layer, what trust assumptions they require, and how execution is secured. The report also evaluates why adoption has remained limited, highlights promising technical paths like BitVM and OP_CAT, and sizes the total addressable market (TAM) for core use cases like collateralized lending and stablecoin swaps. Drawing on Ethereum as a behavioral reference, it estimates how large Bitcoin’s programmable economy could become if trust-minimized infrastructure takes hold.