Parking Example

A full MPCP settlement flow for a parking payment scenario.

Scenario

Vehicle parks at a meter or garage gate. The parking system requests payment. The vehicle evaluates fleet policy and session budget, signs an SPA, and returns the authorization. The parking system verifies the MPCP chain locally and opens the gate.

Artifacts

Artifact	Description
policy-grant.json	Grant derived from policy constraints
budget-auth.json	Unsigned budget authorization
signed-budget-auth.json	Signed budget auth (SBA)
spa.json	Signed payment authorization
settlement-intent.json	Settlement intent
settlement.json	Settlement result
settlement-bundle.json	Combined bundle for verification

Run

npm run build
npm run example:parking

Or:

node examples/parking/generate.mjs

The script creates ephemeral signing keys, generates all artifacts, writes them to JSON files, runs mpcp verify settlement-bundle.json --explain, and exits 0 if verification passes.

Verify Only

If you have already generated artifacts:

npx mpcp verify examples/parking/settlement-bundle.json --explain

The bundle is self-contained (includes public keys) and uses fixed timestamps so it remains verifiable indefinitely.

Demos

Machine Wallet Guardrails

Demonstrates autonomous spend guardrails: policy limits, cryptographic signatures, local verification, tamper detection.

npm run example:guardrails

Offline Payment

Demonstrates offline machine payments: vehicle holds pre-authorized policy chain, completes payment when network is unavailable.

npm run example:offline

See Offline Payments.