Subject: [Ace] draft-ietf-ace-key-groupcomm / Appendix with generalized format for sign_info_entry

From: Marco Tiloca <[email-masked]>
Date: Thu, 15 Apr 2021 09:13:18 +0200

Hello ACE,

Following the discussion at the virtual interim meeting this week (see 
[1] and slides 4-5 at [2]), I have focused on "Option 2" presented in 
slide 5 of [2].

You can find the changes in the commit at [3], and in the Editor's copy 
at [4] --- see last paragraph of Section 3.3.1 as well as the new 
Appendix B. Having this actually written down should make it easier to 
give any feedback :-)

To summarize, this doesn't change the format of 'sign_info_entry' as 
defined in the document body, and doesn't break any 
profile/implementation of this document.

On the other hand, the generalized format in Appendix B:
- Is both retrocompatible and future-proof for future registered COSE 
algorithms, with possibly more than only Key Type as their algorithm 
capabilities.
- If used with any of today's algorithms, it yields again the same 
'sign_info_entry' format defined in the document body.

The points above apply also in case "Option 1" in slide 5 of [2] was 
used, but "Option 2" appears to be cleaner, less invasive and not 
conducive to bad usages of the generalized format by profiles of this 
document.

Feedback are welcome!

Thanks,
/Marco

[1] 
https://datatracker.ietf.org/doc/minutes-interim-2021-ace-07-202104131000/

[2] 
https://datatracker.ietf.org/meeting/interim-2021-ace-07/materials/slides-interim-2021-ace-07-sessa-ace-key-groupcomm-oscore-00.pdf

[3] 
https://github.com/ace-wg/ace-key-groupcomm/commit/025e37429b1bf628abc2e6d94892c8cb04846ad1

[4] 
https://ace-wg.github.io/ace-key-groupcomm/v-12/draft-ietf-ace-key-groupcomm.html

-- 
Marco Tiloca
Ph.D., Senior Researcher

Division: Digital System
Department: Computer Science
Unit: Cybersecurity

RISE Research Institutes of Sweden
https://www.ri.se

Phone: +46 (0)70 60 46 501
Isafjordsgatan 22 / Kistagången 16
SE-164 40 Kista (Sweden)