Re: [dmarc-ietf] Fwd: New Version Notification for draft-srose-dkim-ecc-00.txt

["Murray S. Kucherawy" <[e-mail]>]

On Fri, Apr 7, 2017 at 8:33 AM, Peter Goldstein <[e-mail]> wrote:

> Does this initiative include an intention to update the cryptographic
> guidance from RFC 6376 sections 3.3 and 3.3.3 ?  The proposed charter
> speaks of adding new algorithms, but doesn't discuss deprecating/removing
> old ones.
>

As John said, DCRUP could do this.


> Some specific concerns are:
>
> 1. Expressly forbidding RSA keys < 1024 bits in size - While the fact that
> some major receivers ignore such keys has made this a de facto standard, it
> would be good for the RFCs to reflect best practice here.  And as we saw
> with the ARC discussion, using the DKIM spec as a reference can
> inadvertently result in new standards supporting known insecure practices.
>

I'm not sure about forbidding, but expressly deprecating by removing
mandatory support would certainly be allowed.


> 2. Eliminating SHA-1 - Even at the time of publication RFC 6376
> recommended that signers avoid the use of SHA-1.  Despite this, a simple
> check of my inbox shows that quite a few senders - including a number of
> large, sophisticated ESPs - still use SHA-1 in preference to SHA-256.
> While the recent developed PDF collision attack against SHA-1 is not
> entirely on point, it seems to be further evidence that SHA-1 should not be
> used.  And given the widespread support for SHA-256, this seems like it's
> mostly a configuration issue for senders.
>

Same issue, because the installed base isn't going to update itself quickly
even if we really want it to.

-MSK