Trillian

trillian is a transparent, cryptographically verifiable data store built on Merkle trees that provides append-only logs and verifiable key–value maps. It separates a storage layer from a verifiability layer, letting applications prove inclusion, consistency, and non-existence through compact cryptographic proofs. The system is designed for horizontal scale with gRPC APIs, enabling multiple frontends and sequencers to operate over a shared backend. Common use cases include certificate transparency, package registries, and audit logs where public verifiability or tamper evidence is required. Trillian exposes both “log” and “map” primitives so developers can choose between append-only timelines or verifiable dictionaries depending on their data model. By making verification independent of trust in the operator, trillian helps build systems that are auditable by external parties.