[dmarc-discuss] A bit quiet?

Roland Turner roland.turner at trustsphere.com
Thu Oct 22 19:15:24 PDT 2015

ARC provides a standardised, software-implementable, means for trustworthy forwarders to implement chain-of-custody records and therefore for receivers to reliably and simply automate assessments about messages received through trustworthy paths that are currently both generally too complicated to make other than by hand and - for longer forwarding chains than author->list->recipient - depend upon trusting untrustworthy data from several hops upstream.

The decisions about who to trust remain more-or-less those which receivers already make, ARC extends the distance that that trust can be algorithmically extended. An untrusted bad guy gains nothing, except against a naive receiver who imagines that ARC is magic. See also naive receivers assuming that SPF passing meant that a message was not spam. Likewise DKIM passing. Likewise DMARC passing. The important change here is that, in addition to incorporating an assessment of the trustworthiness of the author and/or the last hop, assessments of the trustworthiness of forwarders enter the picture.

- Roland

        Roland Turner | Labs Director
Singapore | M: +65 96700022
roland.turner at trustsphere.com

From: dmarc-discuss <dmarc-discuss-bounces at dmarc.org> on behalf of Scott Kitterman via dmarc-discuss <dmarc-discuss at dmarc.org>
Sent: Friday, 23 October 2015 04:44
To: dmarc-discuss at dmarc.org
Subject: Re: [dmarc-discuss] A bit quiet?

On October 22, 2015 1:19:51 PM EDT, Franck Martin via dmarc-discuss <dmarc-discuss at dmarc.org> wrote:
>The fun is moving to ARC

How does that actually help? At least as I read the draft, anyone can make up a 'bad' message and an associated made up DKIM signature and then add their ARC stamp claiming the signature was valid when the message arrived?

Scott K

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