VasperaMesh Ledger Specification — `vaspera-mesh-ledger-v2`

An append-only, hash-chained record of AI decisions, externally anchored to Bitcoin and verifiable offline by anyone, with zero trust in the vendor. This page is the versioned, public reference. The standalone verifier implements it from scratch, importing nothing from our code.

1. The hashed preimage (14 fields)

Each row commits exactly these fields, RFC 8785 (JCS) canonicalized, domain-prefixed:

preimage = "vaspera-mesh-ledger-v2\n" + JCS({
  seq, prevHash, chainId, agent, action, model,
  inputs, sources, outputs, confidence,
  decision, decisionReason, policyVersion, createdAt
})
rowHash  = sha256_hex(preimage)

chainId is inside the preimage (anti-substitution: a chain served under the wrong identity fails even if internally consistent). Any column outside this set — reasoning-chain links, encrypted-content pointers, operational telemetry — is not hashed and cannot change a rowHash.

2. Chain rules

Dense ordering: seq starts at 1 and increments by 1 with no gaps.
Linkage: prevHash equals the previous row's rowHash.
Integrity: sha256(preimage) == rowHash and the preimage re-derives from the exported fields.
Immutability: the store rejects UPDATE/DELETE on chained rows (WORM).
No row, no action: a gated action that cannot write its row does not proceed.

3. External anchoring

Chain heads are timestamped via OpenTimestamps; the receipt upgrades to a Bitcoin block attestation. Only the 32-byte head hash leaves the boundary. A verifier cross-checks that every witnessed head still matches the chain — divergence means history was rewritten after being witnessed.

4. Verify it yourself

# fully independent — the script imports nothing from VasperaMesh
curl -O https://vasperamesh.com/api/verifier   # verify-mesh-ledger.mjs
npm i canonicalize
node verify-mesh-ledger.mjs --base https://vasperamesh.com --chain <chain-id>

Exit code 0 only if the chain is fully intact and consistent with every anchor.

5. Regulatory mapping

Framework	Obligation	Discharged by
EU AI Act Art. 12 / 19	Automatic, retained logs of events	WORM hash-chained rows, retained indefinitely; anchors fix them in time
EU AI Act Art. 14	Human oversight & intervention	Enforcing-mode blocks + ledger-stamped approve/deny
ISO 42001 A.6.2.8 / A.9.2	Operation logged; policy documented	Every row carries the policy version in force
NIST AI RMF MEASURE 2.7 / MANAGE 2.3	Trustworthiness & override auditable	Bitcoin anchor + recorded overrides

Generate an auditor-ready, chain-backed evidence pack from the Compliance page.