Re: [dmarc-ietf] ARC vs reject

"Murray S. Kucherawy" <superuser@gmail.com> Mon, 07 December 2020 05:30 UTC

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From: "Murray S. Kucherawy" <superuser@gmail.com>
Date: Sun, 6 Dec 2020 21:30:28 -0800
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To: Michael Thomas <mike@mtcc.com>
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Subject: Re: [dmarc-ietf] ARC vs reject
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On Sun, Dec 6, 2020 at 9:24 PM Michael Thomas <mike@mtcc.com> wrote:

> An idea that i've been rolling around in my head is that the MLM could
> give a sed-like script to rollback the changes. since they know their
> modifications, they can obviously express how to unmodify them. it may have
> less issue with the mime hackery you were thinking about.
>

You'd need a way to assert, and then evaluate, that something equivalent to
"s/.*/spam/g" is a transformation you're not willing to reverse and say
"yep, we're good."  I don't know how you'd go about automating that.

> But as far as your point about spam vectors it is surely just as true
> about ARC, right? at least with recovering the original text i have the
> ability to remove all of the transforms and deliver the original text.  ARC
> not so much. it's all or nothing on the trust front.
>
> But I really think the key thing about all of this is figuring out what
> defines success. That is the most important thing by far.
>
I think ARC, like PSD, is meant to run for a while and see what we've
learned from it.  Maybe it's the silver bullet, or maybe it's ineffective
complexity.  That should be part of the experiment's definition; Section 11
of the ARC RFC does try to capture all of that.

-MSK