{
  "body": "{\"version\":\"1.0\",\"operation\":\"caocao.cities\",\"params\":{}}",
  "timestamp": 1700000000,
  "nonce": "public-signature-vector-001",
  "secret": "demo-only-not-a-real-key",
  "digest": "ndrGqBJ8IeYsPBN+Ik7OxL825nDCBc2GZ7AYXYyYZYU=",
  "canonical": "POST\n/api/v1/open/invoke\n\napplication/json\nndrGqBJ8IeYsPBN+Ik7OxL825nDCBc2GZ7AYXYyYZYU=\n1700000000\npublic-signature-vector-001",
  "signature": "UvlcJ3dShS5930d9vNmaeSMsuBCxxAVtRUUAMjeLpCc="
}