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[openpgp] Re: Certificate discovery over HKP

Andrew Gallagher <andrewg@andrewg.com> Tue, 08 April 2025 19:41 UTC

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Subject: [openpgp] Re: Certificate discovery over HKP
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On 8 Apr 2025, at 19:35, Daniel Huigens <d.huigens=40protonmail.com@dmarc.ietf.org> wrote:
> 
> 
>> we can require that policy file lookups are covered by a
>> TLS certificate, but cannot yet require that SRV records be
>> covered by DNSSEC
> 
> In theory we could require that, it's just a question of whether the
> security gain is worth preventing sites without DNSSEC from using this,
> right?

Right. 

> Also, in the cold-email case, the most serious attack a MITM could do
> is to prevent the OpenPGP cert from being served altogether, and that's
> possible in either case (e.g. by just removing the openpgpkey subdomain
> DNS record).

An MITM could redirect to a malicious keyserver and serve a fake cert with an attacker-controlled encryption subkey. They could even bind the real subkey as a second encryption subkey to make the attack silent.

A

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