[Ace] Scope question

Jim Schaad <ietf@augustcellars.com> Mon, 24 February 2020 18:02 UTC

From: Jim Schaad <ietf@augustcellars.com>
To: draft-ietf-ace-key-groupcomm-oscore@ietf.org
CC: 'Ace Wg' <ace@ietf.org>
Date: Mon, 24 Feb 2020 10:02:17 -0800
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Subject: [Ace] Scope question
Precedence: list

I was starting to code up the encoding of scope and wanted to clarify what
the encoding is.

The text appears to say that the encoding is:

scope = [ groupId: tstr, ?[* role : any ]]

I was expecting this to be more along the lines of

scope = [ + scope_item ]
scopeItem = [ groupId: tstr, ?[* role : any ]]  

This would allow for more than one group to be identified in a single token
which I think is important given some of the statements about only having a
single token for a client.  This does not solve the resource server having
multiple audiences but that is fine.

I am unsure if it makes sense to allow for the array to be removed for scope
in the second example in the event that only one group is specified.  One
byte saved at the expense of more code.

Jim