Re: [dns-privacy] [Ext] Revised opportunistic encryption draft

Peter van Dijk <peter.van.dijk@powerdns.com> Wed, 18 November 2020 20:36 UTC

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From: Peter van Dijk <peter.van.dijk@powerdns.com>
To: "dprive@ietf.org" <dprive@ietf.org>
Date: Wed, 18 Nov 2020 21:36:14 +0100
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Subject: Re: [dns-privacy] [Ext] Revised opportunistic encryption draft
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On Wed, 2020-11-18 at 10:14 -0500, Paul Wouters wrote:
> On Mon, 16 Nov 2020, Brian Dickson wrote:
> 
> > Yes, this is a huge gap in the fundamentals for any privacy architecture (ADoT), which is rooted in the unsigned nature of
> > NS records regardless of the security state of a delegation (DNSSEC or not).
> 
> The IP connection to (small) nameservers will always leak information,
> even if perfectly encrypted and obtained without privacy. Just by
> connecting to say ns1.nohats.ca, any observer knows you are connecting
> to either "nohats.ca" or "libreswan.org".

But not what subdomain, if any, of those you are visiting. I do
recognise that this is on the long tail of things we can try to
protect.

> The only way out of that is a distributed decentralized DNS cache.

I always imagined that, given DNSSEC, we could bittorrent our way out
of this. Then later people imagined we could blockchain our way out of
this - but it hasn't happened yet.

> > Downgrade resistant only if the delegation information is protected (NS names in particular). 
> > Protecting the delegation NS records against an on-path adversary (between resolver and TLD) does not have any nice
> > solutions.
> 
> This is basically the same problem as ESNI. Except ESNI fixed it by
> pulling information from (encrypted) DNS :)

That's "protecting the NS records against snooping", if I understand you correctly. The other problem is protecting the delegation NS records against meddling, for which various partial solutions have been provided but we have zero standardised today.
 
Kind regards,
-- 
Peter van Dijk
PowerDNS.COM BV - https://www.powerdns.com/