{
  "schemaVersion": 1,
  "publicSummaryVersion": "2026-09-30",
  "classification": "PUBLIC",
  "title": "Historical payment-notification verification test",
  "summary": "On 31 August 2026, a laboratory sandbox test verified that an authenticated payment notification added credit once, repeated delivery or another notification for the same order added nothing further, and a forged notification was refused. The simulated payment, order and credit records reconciled. A mock payment service and test signing secret were used; this was not a live card purchase or a test of the hosted checkout page. KeepState’s usage statement is separate from the payment provider’s tax receipt. Later live-payment assurance requires its own evidence.",
  "date": "31 August 2026",
  "scope": "Laboratory or bench evidence; production behavior is not inferred from it.",
  "result": "On 31 August 2026, a laboratory sandbox test verified that an authenticated payment notification added credit once, repeated delivery or another notification for the same order added nothing further, and a forged notification was refused. The simulated payment, order and credit records reconciled. A mock payment service and test signing secret were used; this was not a live card purchase or a test of the hosted checkout page. KeepState’s usage statement is separate from the payment provider’s tax receipt. Later live-payment assurance requires its own evidence.",
  "sections": [],
  "currentDeployment": "Not independently verified by this historical evidence.",
  "canonical": "/evidence/phase-cp-c3"
}