@tunnelmindai/receipt-verify

Part of TunnelMind — the intelligence layer agents call before they trust the internet. Three lenses on one signed corpus: Scry (who is attacking?) · Sigil (who can you trust?) · Tracker Data API (who is watching?). This package serves: the receipt verifier. Apache-2.0. See tunnelmind.ai/standards/receipt-format/v1.

Reference TypeScript verifier for the TunnelMind Receipt Format v1.0. Implements §4 (Verification procedure) end-to-end plus §8 (Revocation) lookups.

Install

npm install @tunnelmindai/receipt-verify

Zero runtime dependencies. Targets WebCrypto SubtleCrypto + fetch — runs on Node ≥18, Cloudflare Workers, Deno, Bun.

Quickstart

import { verifyReceipt } from '@tunnelmindai/receipt-verify';

const receipt = await (
  await fetch('https://data.tunnelmind.ai/v1/receipt/generate?receipt=true', {
    method: 'POST',
    headers: { 'Content-Type': 'application/json' },
    body: JSON.stringify({ event_type: 'agent.action', payload: { foo: 'bar' } }),
  })
).json();

const result = await verifyReceipt(receipt);

if (result.valid) {
  console.log('✓ verified', result.receipt_id, 'signed by', result.key_id);
} else {
  console.error('rejected:', result.errors);
  console.warn('warnings:', result.warnings);
}

What the verifier checks (per spec §4 + §8)

1. Version — receipt_version === "1.0" (verifiers MUST reject unknown majors)
2. Payload hash — recompute 0x + hex(SHA-256(JCS(payload))), compare to payload_hash
3. Signature — reconstruct the signing object (§3 step 2), JCS-canonicalize, verify Ed25519 against the embedded signature.public_key
4. Key bundle resolution — fetch https://tunnelmind.ai/.well-known/receipt-signing-key.json, confirm the resolved key's public_key matches the receipt's
5. Attestation-strength ceiling — reject if receipt.attestation_strength exceeds the resolved key's declared strength
6. Revocation — fetch https://tunnelmind.ai/.well-known/receipt-revocations.json:
   • if signature.key_id is revoked AND the receipt was signed after revoked_at, reject
   • if receipt_id is in revoked_receipts, reject
7. Chain sanity — warn (not reject) if chain.sequence and previous_receipt_hash are inconsistent

The first 3 checks are pure-crypto and require no network. Checks 4-6 fetch well-known feeds, which can be disabled or pre-loaded.

Offline + pinned modes

For high-throughput or air-gapped verifiers, pre-fetch the well-known feeds and pass them in:

import { verifyReceipt, fetchKeyBundle, fetchRevocations } from '@tunnelmindai/receipt-verify';

const [keys, revocations] = await Promise.all([fetchKeyBundle(), fetchRevocations()]);

const result = await verifyReceipt(receipt, { keys, revocations });

For fully-offline verification (pure crypto + embedded public_key only):

const result = await verifyReceipt(receipt, {
  noFetchKeys: true,
  noFetchRevocations: true,
});

Rotation-overlap mode

When the issuer rotates a key, both the old and new key are live for ~24h. During that window, accept a key-bundle mismatch as a warning:

const result = await verifyReceipt(receipt, { allowKeyMismatch: true });

API

verifyReceipt(receipt, opts?)

Main entry point. Returns Promise<VerifyResult>:

interface VerifyResult {
  valid: boolean;
  errors: string[];
  warnings: string[];
  receipt_id?: string;
  key_id?: string;
  attestation_strength?: 'self-asserted' | 'software' | 'tee-tpm' | 'silicon-root';
}

VerifyOptions

Option	Default	Purpose
keys	(fetched)	Pre-fetched KeyBundle to skip the network
noFetchKeys	false	Skip key-bundle resolution entirely
keysUrl	tunnelmind.ai/.well-known/receipt-signing-key.json	Self-hosted issuer override
revocations	(fetched)	Pre-fetched RevocationFeed
noFetchRevocations	false	Skip revocation check entirely
revocationsUrl	tunnelmind.ai/.well-known/receipt-revocations.json	Self-hosted issuer override
allowKeyMismatch	false	Demote key-mismatch error → warning
fetcher	globalThis.fetch	Custom fetch (e.g., for tests)

Lower-level exports

fetchKeyBundle, resolveKey, clearKeyCache, fetchRevocations, isKeyRevoked, isReceiptRevoked, clearRevocationCache, canonicalize, canonicalizeBytes, RECEIPT_VERSION.

Verifying receipts you didn't issue

Receipts are designed to be verifiable by anyone — the public key is embedded in the receipt and validated against TunnelMind's published key bundle. You don't need credentials, an account, or any prior relationship with the issuer.

That said: the key bundle and revocation feed must be retrievable from a source you trust. The defaults point to tunnelmind.ai; for receipts issued by another producer, point keysUrl / revocationsUrl at the producer's well-known endpoints.

Spec drift

The JCS canonicalizer in src/jcs.ts is bit-identical to the issuer-side serializers in scry-server/src/lib/receipt_v1.js and tunnelmind-data-api/api/utils/receipt-v1.js. Any change to one MUST be mirrored across all three. The frozen wire vector lives in this package's test/golden.test.js to catch silent drift.

License

Apache-2.0. The receipt-format spec text itself is CC-BY-4.0 (separately hosted).

Related

• @tunnelmindai/atap — ATAP receipt verifier (different format, complementary use case)
• @tunnelmindai/eat — EAT Profile v0.1 verifier (RFC 9711 alternative serialization of the same claim set)
• agent-onboarding.md — the 5-call golden path that uses these receipts end-to-end