json_schema: {
      "$schema": "http://json-schema.org/draft-04/schema#",
      "type": "array",
      "items": {
          "type": "object",
          "properties": {
              "shared_secret": {
                  "type": "string"
              },
              "header": {
                  "type": "string",
                  "pattern": "^[a-zA-Z0-9]([a-zA-Z0-9-]+[a-zA-Z0-9])?$"
              },
              "algorithm": {
                      "enum": [
                          "hmac-md5",
                          "hmac-sha1",
                          "hmac-sha256",
                          "hmac-sha384",
                          "hmac-sha512"
                      ]
              }
          },
          "additionalProperties": false,
          "required": [
              "shared_secret",
              "header",
              "algorithm"
          ]
      }
  }
  