Re: [MLS] Use Cases for avoiding Forward Secrecy

Phillip Hallam-Baker <phill@hallambaker.com> Thu, 01 March 2018 16:34 UTC

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From: Phillip Hallam-Baker <phill@hallambaker.com>
Date: Thu, 1 Mar 2018 11:34:31 -0500
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To: Russ Housley <housley@vigilsec.com>
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Subject: Re: [MLS] Use Cases for avoiding Forward Secrecy
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On Thu, Mar 1, 2018 at 10:11 AM, Russ Housley <housley@vigilsec.com> wrote:

>
> Generally, I think the right answer to these, however, isn't to modify the
> messaging protocol but rather to add that functionality on the messaging
> app over the top. That also is a much easier way to do new device history
> sync
>
>
> This is similar to the approach used in some email environments.  The
> email message is decrypted for reading, and then encrypted in a separate
> archive key for storage.
>
> Russ
>

​It is a valid approach and it might be the right approach.
​
​But what we have right now is a rather complex proposal that may or may
not be correct and may or may not be addressing the real requirements and
may or may not be addressing them in the most straightforward fashion.

So far I have seen a lot of defensive responses and one individual whose
behavior was bullying. Now the fact that I cannot be bullied out of my
opinions does not make ​the experience of people making personal attacks
any more pleasant for me.

More importantly, I am concerned that what has been more or less explicitly
stated is 'we have our proposal and if you don't like it then bog off'.

I don't think that language encourages honest debate about the limitations
of the proposal or identifying the flaws.

I would much rather the IETF endorse no proposal than one that only
navigates the process because a group of bullies shouted down anyone who
was critical of it. We saw that happen with DANE we saw it happen with
CBOR. CBOR does work but the consequence of shutting down the voices saying
that we needed a binary format that precisely matches the semantics of JSON
is that we had to spin up a separate COSE working group to repeat the work
of JOSE rather than simply apply the encoding.


The assumption of most here is that the requirements are easy and the
cryptography is hard. That is precisely the wrong way round. If we really
understand what the requirements are, the cryptography follows almost
directly. It is getting to the understanding of the requirements that is
the hard part.