[Cryptography] DNSSEC = completely unnecessary?

Paul Wouters paul at cypherpunks.ca
Tue Nov 5 20:48:49 EST 2013


On Tue, 5 Nov 2013, Greg wrote:

> Here's two from Moxie (now I know I'm in good company):
>
>       "So unfortunately the DNSSEC trust relationships depend on sketchy organizations and governments, just like the current CA
>       system. Worse, far from providing increased trust agility, DNSSEC-based systems actually provide reduced trust agility."
> http://www.thoughtcrime.org/blog/ssl-and-the-future-of-authenticity/

I've answered Moxie (and others) on this before:

https://nohats.ca/wordpress/blog/2012/04/09/you-cant-p2p-the-dns-and-have-it-too/

ExecSum: you cannot avoid trust, making it hierarchical gives the least
trust to parties. You monitor those you have to trust more, more
closely.

>       "We had this map of the EFF's SSL Observatory data on what countries are currently capable of intercepting secure
>       communication under the CA system. Under [DNSSEC/DANE], it would look like this."
> https://www.youtube.com/watch?v=Z7Wl2FW2TcA#t=33m43s
> 
> (He shows a completely red map, indicating all countries)

That's a nonsense argument. Abuse of such powers, unlike the plethora of
CA certs, would need to be world visible, that is untargetted. It would
be very very visible. It is a huge win over CAcerts that can target
individuals with specifically crafted signed certs.

With dnssec, if the Government of Canada causes my nohats.ca to be
modified (appear red on your above map), then my domain's public
information changes. I would notice that. This is not an invisible
MITM like some CA cert injection.

Which ever organisation you pick for the initial "name and crypto key
lookup" has that power. What you must do is track and monitor, so ensure
that power is not abused.

It's very easy to say "trust no one". But if you want to talk to people,
you need to place trust in some. All replacements I have seen of
DNS(SEC) just move the problem elsewhere.

You want to have a hierarchical trust pyramid. You can monitor, and even
safeguard by picking some parts on the pyramic you trust more than the
top (root). This both scales and keeps the trust needed to be
given to a minimum. The higher in the hierarchy a trust organisation is,
the less targetted violation of trust they can do. Moving down, trust is
only handed down to entities that can only betray themselves, not
others.

Any kind of "harvest and vouch" or "public ledger" solution is going to
be riddled with false positives, due to the delay between
publisher/owner of the data and the trustee/ledger updating itself.
Plus you don't even _know_ which parties it is that you are given
trust to when accessing "N of M" entities to determine truth.

Paul


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