3DS Challenge object

{
  "$schema": "https://json-schema.org/draft/2020-12/schema",
  "$id": "#/components/schemas/challenge",
  "title": "3DS Challenge object",
  "type": "object",
  "description": "Represents a challenge object for 3DS authentication",
  "properties": {
    "challenge_method_type": {
      "type": "string",
      "description": "The type of challenge method issued to the cardholder",
      "enum": [
        "OUT_OF_BAND"
      ]
    },
    "start_time": {
      "type": "string",
      "description": "ISO-8601 time at which the challenge has started",
      "format": "date-time"
    },
    "expiry_time": {
      "type": "string",
      "description": "ISO-8601 time at which the challenge expires",
      "format": "date-time"
    },
    "app_requestor_url": {
      "type": [
        "string",
        "null"
      ],
      "description": "Fully qualified app URL of the merchant app. This should be used to redirect the cardholder back to the merchant app after completing an app-based challenge. This URL will only be populated if the 3DS Requestor App is provided to the 3DS SDK.",
      "format": "uri"
    }
  },
  "required": [
    "challenge_method_type",
    "start_time",
    "expiry_time"
  ]
}