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Re: [dmarc-ietf] ARC questions

Michael Thomas <mike@mtcc.com> Mon, 23 November 2020 20:54 UTC

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From: Michael Thomas <mike@mtcc.com>
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Date: Mon, 23 Nov 2020 12:54:35 -0800
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Subject: Re: [dmarc-ietf] ARC questions
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On 11/23/20 12:15 PM, Brandon Long wrote:
>
>
> This recent article also goes into things that DKIM signatures imply:
> https://blog.cryptographyengineering.com/2020/11/16/ok-google-please-publish-your-dkim-secret-keys/ 
> <https://blog.cryptographyengineering.com/2020/11/16/ok-google-please-publish-your-dkim-secret-keys/>
>
> Perhaps this all means that DKIM has been used for more than it was 
> intended for.

It is a quirk that we didn't consider at the time. You can't count on 
that property because providers can change their selectors at any time. 
That said, there is an awful lot of hand wringing for not much gain. 
It's not like you need cryptographic non-repudiation to be pretty sure 
something wasn't forged. That and non-repudiation has its benefits as well.

Mike

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