Glossary

Anchor — a Merkle root written once to the blockchain. Immutable; the chaincode rejects any overwrite.

Batch — a group of pending records folded into a Merkle tree and anchored together. Identified by a batch_id.

Chaincode — the Go smart contract on Hyperledger Fabric that stores and guards the anchors.

Domain — a client-chosen namespace for records (/api/v1/{domain}/records).

Hash (v2) — a record’s integrity fingerprint: SHA-256(0x00 ‖ lp(id) ‖ lp(timestamp) ‖ lp(source) ‖ lp(canonical(payload))).

hash_fields — optional list restricting which payload keys feed the hash.

hash_version — the hashing scheme used for a record (v2; absent = legacy v1).

Merkle root — the single hash at the top of a Merkle tree; it commits to every record in the batch.

Merkle tree — a binary tree of hashes; leaves are record hashes, internal nodes are SHA-256(0x01 ‖ left ‖ right). Odd nodes are promoted, not duplicated.

MSP — Membership Service Provider; a Fabric organization’s identity authority. Used as a tenant fallback when no tenant certificate attribute is present.

Record — the unit of data: source + JSON payload, with a server-assigned id, timestamp, and hash.

Tenant — an isolation boundary. Records are isolated per (tenant, domain); ledger isolation is enforced by the caller’s signed identity.

WAL — write-ahead log; records are fsync-ed to it before acknowledgement, so an acknowledged write survives a crash.

Write-once — the property that an anchored Merkle root can never be overwritten.