Subject: [Ace] [ace] key-groupcomm-oscore - Key material from the Group Manager

From: Marco Tiloca <[email-masked]>
Date: Mon, 3 Feb 2020 10:15:55 +0000

Hello ACE,

Here I elaborate more on the open point #3 that I raised during the
interim meeting on Friday, 31st of January --- see slide 5 at [1].

According to the API defined in ace-key-groupcomm , a group member can
issue the following two requests to the Group Manager:

(A) GET to /group-oscore/GROUPNAME

This is intended to retrieve the latest group key material, i.e. what is
pertinent to all group members as related to the group [2].

(B) GET to /group-oscore/GROUPNAME/NODENAME

This is intended to retrieve the latest group key material - as in (A) -
, plus the latest individual key material for the requesting node. In
this profile, the individual key material is the Sender ID that that
node uses in the group [3].

As I mentioned at the interim, now both (A) and (B) practically return
the same thing. In fact:

1) Both (A) and (B) return the parameters 'gkty', 'key' and 'num'.

2) Both in (A) and (B), the 'key' parameter includes 'clientId', which
specifies the Sender ID of the requesting node, just implicitly reusing
the detailed description of the 'key' content in [4].

That is, (A) currently goes beyond what is actually intended by the
general interface of ace-key-groupcomm , i.e. it returns more
information than intended.

A fix can simply be clarifying the specific content of 'key' in [2],
i.e. explicitly saying to not include 'clientId' in the 'key' parameter
for responses from the GET in (A).

Thoughts?

Thanks,
/Marco

[1]
https://datatracker.ietf.org/meeting/interim-2020-ace-02/materials/slides-interim-2020-ace-02-sessa-draft-ietf-ace-key-groupcomm-oscore

[2]
https://tools.ietf.org/html/draft-ietf-ace-key-groupcomm-oscore-04#section-6.1

[3]
https://tools.ietf.org/html/draft-ietf-ace-key-groupcomm-oscore-04#section-6.2

[4]
https://tools.ietf.org/html/draft-ietf-ace-key-groupcomm-oscore-04#section-4.4

-- 
Marco Tiloca
Ph.D., Senior Researcher

RISE Research Institutes of Sweden
Division ICT
Isafjordsgatan 22 / Kistagången 16
SE-164 40 Kista (Sweden)

Phone: +46 (0)70 60 46 501
https://www.ri.se