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Re: [dmarc-ietf] ARC Crypto Algorithm Selection

Seth Blank <seth@sethblank.com> Tue, 23 October 2018 15:25 UTC

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From: Seth Blank <seth@sethblank.com>
Date: Tue, 23 Oct 2018 08:25:03 -0700
Message-ID: <CAD2i3WOaAoiDV-t6BNa4rQVWLjhr4Q0-TcQyb7cfjadLEDRDQA@mail.gmail.com>
To: Scott Kitterman <sklist@kitterman.com>
Cc: dmarc@ietf.org
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Subject: Re: [dmarc-ietf] ARC Crypto Algorithm Selection
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ARC inherits all the DKIM mechanisms by reference. So whatever’s valid for
DKIM (the list you provided) is what’s valid for ARC.
On Tue, Oct 23, 2018 at 03:58 Scott Kitterman <sklist@kitterman.com> wrote:

> I've started looking at updating dkimpy to align to the current versions
> of
> the specification.
>
> Last time I looked at this particular issue, ARC could use any algorithm
> that
> DKIM uses.  As I recall, that was once of the stimuli for the DCRUP
> working
> group (to avoid having rsa-sha1 be valid for ARC by obsoleting it in DKIM).
>
> It looks like this discussion has been moved to a new draft,
> https://tools.ietf.org/html/draft-ietf-dmarc-arc-multi-01 (although the
> reference is wrong,
> https://tools.ietf.org/html/draft-ietf-dmarc-arc-multi-02
> is current.
>
> Unfortunately, I don't find any actual guidance on what algorithms are
> currently used.  Secion 6, Phases of Algorithm Evolution, gives some
> process
> (which seriously needs revision - I thought we all knew flag days don't
> work
> at Internet scale), but no actual guidance.
>
> DKIM, as updated by the DCRUP work, has two valid crypto algorithms:
>
> rsa-sha256
> ed25119-sha256
>
> One has been obsoleted:
>
> rsa-sha1
>
> Which among those is valid for ARC and how do I know?
>
> Scott K
>
> _______________________________________________
> dmarc mailing list
> dmarc@ietf.org
> https://www.ietf.org/mailman/listinfo/dmarc
>

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