Two pieces the composer has been waiting for since it was written.
**The credential has to outlive its own minting.** On the bus the mesh runs on
today an account is a management call: mint a password, hand it over, seal the
plaintext to whoever will use it, keep nothing — which works because the broker
remembers. Here the users are one file, rewritten whenever any of it changes, so
keeping nothing would mean the first person's access change silently blanking
every module's password. So a bus user's bcrypt hash is now recorded, keyed by the
username the file needs, and the plaintext comes back exactly once. Verified
against a real store that the hash verifies the password it was made from, that
the password itself is not in there, that minting again rotates rather than adds,
and that forgetting a node takes its host's and its modules' credentials with it.
**Permissions are not stored, and that is the point.** Only the credential is
kept. Authority is derived from what each module declares, every time the file is
written (ADR 0043) — a stored permission list would be a second account of a
user's authority, able to disagree with the records it came from, and both would
look internally consistent while they did.
`Users` derives the list: the controller always first and always present, one
user per node, one per module per node, one per live token, one per person. Two
users with one name is refused where both can be named, rather than left to be
whichever one the server happened to read. A user the mesh has never minted a
password for is *named* rather than dropped or written as a user anybody is:
that is an ordinary situation with an obvious remedy, and the caller decides
whether a partial file is worth writing.
What remains of 1.7: delivering the file to the node that runs the server, and
minting at enrolment and assignment — which is transport-coupled, because a node
on the old bus must not be handed a credential for the new one.
jschoubben
0560c792d8