ndncert/debian/ndncert-ca.conf

{
  "ca-list":
  [
    {
        "ca-prefix": "/example",
        "issuing-freshness": "720",
        "validity-period": "360",
        "probe": "Get the PIN code from me :D",
        "ca-info": "Example CA",
        "supported-challenges":
        [
            { "type": "PIN" }
        ]
    }
  ]
}