Re: [saag] On PKI vs. Pinning (SAAG 108 preview)

On Tue, 28 Jul 2020 at 21:09, Stephen Farrell <stephen.farrell@cs.tcd.ie>
wrote:

>
>
> On 28/07/2020 20:56, Ben Laurie wrote:
> > I'm a little surprised by this conversation. Why would SAAG want to
> support
> > a practice that flies in the face of everything we know about key
> > management?
>
> Sorry if I gave the wrong impression. I agree with you
> that pinning to application keys is a bad idea.
>
> I do think there's a role for pinning to CAs

With you up to here.

> that you
> already gotta trust,

Why?

> as a way to fail rather than allow
> a MITM, for the cases where that's better.
>

Surely this is not what CAs are for? They're for succeeding rather than a
MITM, aren't they? That does suppose revocation that actually works (which
I would suggest is a more useful thing to work on than pinning).

Also, to be clear, pinning CAs is only deferring the problem - and, in
fact, without CA blacklisting, is not a great deal better.

Well. That escalated fast.

>
> S
>
> >
> > On Tue, 28 Jul 2020 at 20:49, Stephen Farrell <stephen.farrell@cs.tcd.ie
> >
> > wrote:
> >
> >>
> >>
> >> On 28/07/2020 20:42, Benjamin Kaduk wrote:
> >>> Sorry for the clumsy description.  Basically, if you squint hard, you
> >> could
> >>> claim that at least some types of pinning are actually a PKI, just a
> >>> degenerate PKI.
> >>
> >> Ah gotcha.
> >>
> >> ISTM more useful to treat pinning as an adjunct to whatever
> >> PKI is used by the application that can be MITM'd and not
> >> bother with pinning as a potential replacement for that
> >> PKI. There's nothing wrong with an application being based
> >> on it's very-own PKI of course, but seems less useful for
> >> the IETF to try describe pinning for custom protocols where
> >> we don't know the details.
> >>
> >> Cheers,
> >> S.
> >> _______________________________________________
> >> saag mailing list
> >> saag@ietf.org
> >> https://www.ietf.org/mailman/listinfo/saag
> >>
> >
>