Re: [MLS] recharter text

Rohan Mahy <rohan.mahy@wire.com> Mon, 13 November 2023 06:46 UTC

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From: Rohan Mahy <rohan.mahy@wire.com>
Date: Mon, 13 Nov 2023 07:45:43 +0100
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To: Brendan McMillion <brendanmcmillion@gmail.com>
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Subject: Re: [MLS] recharter text
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A couple of comments inline:

On Sun, Nov 12, 2023 at 11:17 PM Brendan McMillion <
brendanmcmillion@gmail.com> wrote:

> "Support for common operational patterns in messaging applications" -- On
> the other hand this seems too broad, in that arbitrary endless work could
> fit under this umbrella. The two drafts listed under this category are
> "Last resort KPs" and "KP context". I've been concerned about the utility
> of these drafts. They specify that new information be put inside of the
> KeyPackage and signed. But I don't believe there's much security value in
> having this information signed. The drafts also require application logic
> outside of the extension to work correctly, so using the extension is not
> any operationally simpler than a solution that's entirely application-level.
>

Are you calling my baby ugly?   ;-)

Brendan, I don't think you are considering the system implications of
claiming KeyPackages. In many systems, the client that generates the
KeyPackages is offline when they are claimed. How would the requester of a
KeyPackage get an appropriate KeyPackage from the target's provider, and
how would the target's provider know which KeyPackage to provide unless we
specify the necessary fields? Sure, if the target is always online you can
do this at the application level, but the target is not always online.


> I'd also like to see a call-out to work on support for the "user trees"
> idea that was mentioned during the meeting.
>

While I am super excited about this, we don't even have an internet draft
yet. Maybe we could finish some of the work that is close to publication,
and then add this? I like the idea of doing a lite recharter every 6
months, and I think this would be consistent with that approach.

Thanks,
-rohan