Re: Agenda, security, and monitoring

--On Monday, February 03, 2014 09:05 -0500 Theodore Ts'o
<tytso(_at_)mit(_dot_)edu> wrote:

> On Sun, Feb 02, 2014 at 06:44:58PM -0600, Pete Resnick wrote:
> > I agree that authentication is irrelevant in this context. But
> > that's leads me to agree with Dave on a central point (hence
> > the little I-D we've been banging on and submitted to the
> > STRINT folks): The problem with PGP and S/MIME is that they
> > require authentication in order to start using encryption,
> > and since authentication is both irrelevant to this *and* a
> > pain to do...
> We should be a bit careful about our terms here.  If we don't
> care about authentication at all, one solution is to just do
> hop-by-hop diffie hellman (or TLS with completely unchecked
> certificates). That's actually pretty easy, and it's not a bad
> ...
> As a specific example, if all you want to do is make sure that
> someone really controls the e-mail address named in the PGP
> key identity, then you could do an web-automated version of
> "CAFF" (Certifying Authority Fire and Forget)[1].
>
> [1] http://manpages.ubuntu.com/manpages/hardy/man1/caff.1.html
>
> So imagine a web service, running on tools.ietf.org, (a) which
> makes someone prove that they have control over a specified
> e-mail address, by mailing them a URL with a one-time code
> embedded in it, then (b) asks them to upload a PGP key, and
> then (c) it sends back to that e-mail address their PGP key
> signed with a registry key --- but the signature is encrypted
> so only someone with the private key of the PGP key can
> decrypt it.  This basically proves that the submitting entity
> has control over both the e-mail address and the private key
> of the PGP key that they are requesting be certified.
>
> If this is being done via https, and you trust that the CA for
> ietf.org is doing a competent job, and *all* CA's and sub-CA's
> trusted by your browser are doing a competent job, then this
> will basically do what you want, and it doesn't require people
> to show up at a PGP signing party.  The user experience
> becomes that which is needed when you sign up for a Google, or
> Yahoo, or any other web site which demands that you prove that
> you have a valid e-mail address.
Right.  Very weak authentication of individual identity but,
given the above assumptions, decent-or-better authentication of
ownership of keys, addresses, and identity-persistence.  Whether
that is good enough depends on one's concerns and attack
scenarios -- for the IETF list, I'd imagine almost no one would
care.  And, of course, the requirement of competence by "*all*
CA's and sub-CA's trusted by your browser" doesn't pass a laugh
test these days unless one is paranoid and geeky enough to edit
browser CA lists down to those one actually has reason to trust.

That is why I think it is worthwhile to tease out what we really
want and need, not say blanket things like "no authentication
needed" as Pete's note seemed to.

     john