Re: [saag] Whether TOFU should be considered in secure DHCPv6?

Viktor Dukhovni <ietf-dane@dukhovni.org> Thu, 01 September 2016 03:01 UTC

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Subject: Re: [saag] Whether TOFU should be considered in secure DHCPv6?
From: Viktor Dukhovni <ietf-dane@dukhovni.org>
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> On Aug 31, 2016, at 10:46 PM, Viktor Dukhovni <ietf-dane@dukhovni.org> wrote:
> 
> Except for (allegedly) EV certs, the entire Web PKI runs on TOFU,
> except that it happens invisibly (swept under the rug) between the
> CA and the purported domain owner.
> 
> Thus DV certs are TOFU for public consumption, where the CA gets
> to regurgitate the same TOFU to feed all the relying parties.

I should perhaps add that the problem with TOFU is not so much
that is especially weak authentication, but rather that is much
too fragile for peering to a large number of peers.

When uses TOFU for SSH to a small set of servers, or to connect
to a small, mostly stable set of networks, it can be a reasonable
fit.  When one uses TOFU with a large dynamic set of peers with
keys relatively frequently becoming stale TOFU, then it becomes
a rather poor user experience, and is counter-productive.

-- 
	Viktor.