Re: [Trans] DNSSEC also needs CT

Nico Williams <> Thu, 22 May 2014 17:38 UTC

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Date: Thu, 22 May 2014 12:38:36 -0500
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From: Nico Williams <>
To: Stephen Kent <>
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Subject: Re: [Trans] DNSSEC also needs CT
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On Thu, May 22, 2014 at 12:21 PM, Stephen Kent <> wrote:
>> DNSSEC is a PKI [of sorts; please, no need to pick nits about that].
> agreed.
>> It stands to reason that DNSSEC should have similar trust problems as
>> PKIX.  I believe it does indeed.
> PKIX, per se, does not have the trust problems that seem to motivate
> CT; the Web PKI does. That PKI has always had a serious problem because
> any TA can issue a cert for any Subject, irrespective of the Subject name.
> because DNSSEC intrinsically incorporate the equivalent of PKIX Name
> Constraints, it does not suffer from that specific problem. That's not to
> say that mis-issuance is not possible in DNSSEC, but rather that its
> effects are more limited.

I've already said that DNSSEC fundamentally has strong naming
constraints, whereas the TLS web server PKI doesn't (and worse: has
been deployed with none).

However, I don't think it necessarily follows that having name
constraints -> no need for CT.

CT is about keeping CAs honest.  In the TLS web server PKI there are
very many CAs to keep honest, therefore anything that helps automate
that task is greatly helpful.

DNSSEC "CAs" also could use being kept honest, even if none of them
have yet failed to be honest.

>> It follows that things like CT that we're applying to PKIX should be
>> applied to DNSSEC as well, where possible.
> maybe.

Sure, maybe.