Re: [MLS] AppAck

Joel Alwen <> Mon, 23 November 2020 16:34 UTC

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From: Joel Alwen <>
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Date: Mon, 23 Nov 2020 17:34:22 +0100
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Subject: Re: [MLS] AppAck
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If using the AppAck proposal is not mandatory and it would be useful to several
of the envisaged deployments (which sounds to be the case) I don't see this as
being too problematic. Though I do agree that other message loss policies also
make sense. (E.g. wanting eventual agreement on total ordering.)

Moreover, it should be quite easy to support these proposals since they have
almost no effect on the cryptographic state so are easy to process. Its really a
UX thing I think.

On 22/11/2020 23:07, Brendan McMillion wrote:
> b.) clients only want to validate receipt of messages at a Commit,

Not sure why you say this is implied by how AppAck is defined. From the PR:

> * The application could have a client send an AppAck whenever an application
>   message is sent, covering all messages received since its last AppAck.  This
>   would provide a complete view of any losses experienced by active members.
- Joël