MPP machine payment security and delegated authorization

What the protocol establishes

MPP is a payment-method-agnostic HTTP 402 authorization framework for machine payments. MandateShield does not parse raw MPP challenges or credentials, select a payment method, or execute settlement today. A trusted integrator can normalize the final provider, resource, amount and currency into a signed CUSTOM envelope before constructing or disclosing the MPP payment credential.

Five checks before execution

1. Resolve the final MPP provider, resource, amount and currency before authorization.
2. Normalize those exact terms into a MandateShield CUSTOM envelope.
3. Bind the envelope to fresh authority signed by the account-pinned issuer.
4. Enforce per-attempt and cumulative budgets atomically across concurrent agents.
5. Require the trusted gateway to consume the reservation once before constructing or submitting the MPP credential.

The gap MandateShield closes

A valid MPP challenge and credential establish payment-protocol semantics, not that a person or enterprise approved the exact provider, resource and price selected by the agent.

MandateShield normalizes execution facts and returns a deterministic decision with exact findings. Strict v2 verifies supported evidence and returns an ES256-signed receipt with public transparency; it complements the protocol's wider trust and settlement chain.