Subject: [Ace] remarks on draft-tiloca-ace-oscore-gm-admin-00

From: Jim Schaad <[email-masked]>
Date: Wed, 20 Nov 2019 07:13:44 +0800

This is just going to be a high level review on how things are done rather
than a detailed review on each line of text.

1. - Go and read that CoRE Pub-Sub update document - you know the one that
Klaus and friends have not managed to get written since the model proposal
was done way back when.

2.  Re-write this to use CoRAL - Yes I know that this makes another
dependency on getting it published from the CoRE group, but I don't want to
do things multiple times.

3.  I think that this document really needs to be able to be used with
HTTP/JSON as well as CoAP.   If you can get the JSON version of CoRAL from
Klaus then this falls out without any work.

4.  Are you making it a requirement that the group name be the same as the
group identifier assigned by the "group_name" parameter?  If so then having
some type of title and description would seem to be almost mandatory.

5.  There needs to be some parameters around pointing to the correct AS and
so forth.  The management API may reject because it does not trust the AS.
Don't assume that this is a single value for the AS either.

6.  You are missing a lot of management detail on the POST to the group
node.  Some of the things that are missing would be:
a)  Is the group active or inactive
b) How does the server react if you change a the content encryption
algorithm, is this a simple re-key operation or is it more complicated
c) How does the server react if you change the signature algorithm?  This
would seem to be a much harder thing to do if the group is not empty or not
active as everybody is going to need to re-join.
d) Other parameter that are changed may be just as bad as changing the
signature algorithm - how the re-key is done jumps immediately to mind.

7.  Is there currently any way for a KDC to signal to all of the members
that have joined that the key group no longer exists?  A DELETE would seem
to indicate the need to be able to do this.

Jim