Signed configuration
====================

A config file is unusable unless it is an Ed25519 wrapper::

   { "payload": { ... }, "sig": { "alg": "ed25519", "key_id": "...", "signature": "hex" } }

Select algorithms inside **payload** (the signed object):

* ``crypto.mode``: ``npe`` | ``lab-xor`` | ``plain-lab``
* ``routing.mode``: ``passthrough``
* ``admin.history_cube``: cube id for admin-history
* ``crypto.system_key_id``: system public key id
* ``logging.mode``: ``summary``

After an admin console change: sign again, then append previous file, new
file, and unified diff to the admin-history DataCube
(``verae.admin.history.append``).