Re: [IPsec] replacing PSKs: CFRG and PAKE

[Michael Richardson <[e-mail]>]

Nico Williams <[e-mail]> wrote:
> On Mon, Dec 10, 2018 at 09:20:54PM -0500, Michael Richardson wrote:
> > Paul Wouters <[e-mail]> wrote:
> > > > yes, typo, "not for road-warrior"
> > >
> > > I understood. I disagree with the “not”. Road warriors using group psk is a
> > > thing, sadly.
> >
> > But they aren't cross-domain, they can do EAP-foobar, and they could use a
> > certificate without a lot of hassle about what set of trust anchors.
> >
> > If we stick to the site-to-site then I think we can do something rather
> > simple and quick, and our security considerations section will be much
> > simpler.
>
> I mean, if road warriors should always be using either EAP or user
> certs, then we don't need PAKE for anything because presumably the
> shared keys used in PSKs are strong enough that PAKEs don't improve
> security and only slow things down...

It's the enterprise-to-enterprise connection that is hard to convert to
certificates for the reasons that Paul explained.

> (I'm assuming you mean to use an EAP method like EAP-PWD (RFCs 5931 and
> 8146), yes?)
>
> Assuming you can always use EAP, the only real reasons to use a PAKE in
> IKEv2 are:
>
>  - you're not entirely sure that you don't have weak PSKs and would like
>    to strengthen them

I think that this is the major reason.

>
>  - you don't always want EAP for users who don't have certs for reasons
>    that escape me
>
>    (I wouldn't object, but if EAP fits the bill as to PAKE already, then
>    thw WG could object to spending its resources on adding PAKE to
>    IKEv2.)

I think that a user-oriented PAKE is more useful if it can be backended into
a AAA infrastructure, which EAP can.
A site-to-site PAKE is more useful if it isolated from any AAA
infrastructure.

--
]               Never tell me the odds!                 | ipv6 mesh networks [
]   Michael Richardson, Sandelman Software Works        | network architect  [
]     [e-mail]  http://www.sandelman.ca/        |   ruby on rails    [


--
Michael Richardson <[e-mail]>, Sandelman Software Works
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