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Re: [dmarc-ietf] indeterminisim of ARC-Seal b= value

"Murray S. Kucherawy" <superuser@gmail.com> Thu, 30 March 2017 08:57 UTC

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From: "Murray S. Kucherawy" <superuser@gmail.com>
Date: Thu, 30 Mar 2017 03:57:41 -0500
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To: Scott Kitterman <sklist@kitterman.com>
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Subject: Re: [dmarc-ietf] indeterminisim of ARC-Seal b= value
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On Mon, Mar 27, 2017 at 11:49 PM, Scott Kitterman <sklist@kitterman.com>
wrote:

> What's more difficult to is identify all the ways that things get
> reordered,
> mangled, etc as they transit the various elements of the mail architecture.
> If you over specify the allowed order, aren't you risking increasing the
> brittleness of the solution.
>

I think Peter's proposal (and he can correct me if I'm wrong) is only to
constrain signers.  Verifiers are still expected to handle everything weird
that the infrastructure might do.


> If test cases are automatically generated, then they are cheap and we
> shouldn't worry about unduly constraining things to keep the number
> small.  As
> long as, at some point, the test cases are validated against multiple
> implementations, I think it's fine.  If you've got a handful of
> implementations, then the risk of them all having the same bug is pretty
> low.
>

That sort of organic validation of implementations seemed to work for
DKIM.  The unknown here is whether ARC will be as successful with that
model.

-MSK

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