cc/examples/digital_signatures/digital_signature_private_keyset.json

{
  "primaryKeyId": 1487078030,
  "key": [
    {
      "keyData": {
        "typeUrl": "type.googleapis.com/google.crypto.tink.EcdsaPrivateKey",
        "value": "Ek0SBggDEAIYAhohANUKuRXZHBD8rPcB5M6+pmgVSjk3gLSD/htdVvbrfbnPIiAXepWekQPRS74qUTMEwN6nXeizXucBxDk0SoKoeqShOBogbJEwIZASdx42tIitAe8UoBxWyi11Mq+HnWNtcQWkG18=",
        "keyMaterialType": "ASYMMETRIC_PRIVATE"
      },
      "status": "ENABLED",
      "keyId": 1487078030,
      "outputPrefixType": "TINK"
    }
  ]
}