Re: [dns-privacy] Alternative signalling propsals

[Stephen Farrell <[e-mail]>]

Hiya,

On 15/12/2018 00:37, Daniel Kahn Gillmor wrote:
> i think you're suggesting some sort of "starttls"-like mechanism --
> start a DNS connection to an authoritative server, and then the server
> lets you know "hey you might also want to try me in the future via
> private channels"
> 
> is that what you're proposing?

I wasn't proposing, just asking:-) But yes, a starttls like scheme
could be one approach.

> if so, it has the unsatisfying aspect common to all starttls-like
> proposals: it can be trivially stripped.
> 
> it is also unsatisfying in the DNS world because there typically isn't
> a handshake -- the first packet contains the sensitive data that you
> might want to keep private.
> 
> It could certainly help over the longer term against a passive monitor
> -- the initial privacy leak could be amortized over many future
> communications between the resolver and the authoritative -- but it
> still leaves the first connection to that server unprotected even
> against passive attack, which is something that signalling in the name
> could potentially avoid.

Sure, I don't disagree with the above, and I wasn't arguing for
this, more wondering for now if there're any gotcha reasons why it
can't work. That said, perhaps one of the other trade-offs here is
related to the potential ease/speed of deployment - if a mechanism
that's TOFU-like or that needs pinning leaks a little at first but
were easier to deploy and more likely to spread, (say if all that
were needed was a s/w update), then that's something to take into
consideration.

Cheers,
S.