{
    "id": "https://letsencrypt.org/schema/01/challengeRequest#",
    "$schema": "http://json-schema.org/draft-04/schema#",
    "description": "Schema for a challengeRequest message",
    "type": "object",
    "required": [
        "type",
        "identifier"
    ],
    "properties": {
        "type": {
            "enum": [
                "challengeRequest"
            ]
        },
        "identifier": {
            "type": "string"
        }
    }
}