Re: [TLS] draft-ietf-tls-tls13 posted

On Thu, Oct 27, 2016 at 4:27 PM, Kazuho Oku <kazuhooku@gmail.com> wrote:

> Hi,
>
> Thank you for posting draft-18, and thank you for the simplification of
> RMS.
>
> I have finished implementing resumption and early-data in picotls. The
> effort started just before draft-17 was published, so it would be fair
> to say that my effort is solely based on the up-to-date specification.
>
> I am happy to report that all I have found is one minor issue.
>
> The issue I saw is discordance between PSKIdentity.identity and
> NewSessionTicket.ticket.
>
> In draft-18, PSKIdentity.identity is defined as <0..2^16-1>. OTOH
> NewSessionTicket.ticket is <1..2^16-1>.
>
> Is there any reason to only allow a zero-length identity for the former?
>
> My understanding is that when resuming a session, the value of
> NewSessionTicket.ticket is sent as PSKIdentity.identity. So to me, it
> seems more natural if the permitted range of the two arrays were
> equal.
>
> Please forgive me for the fuss if the difference is intentional.
>

Well, you could have an external PSK which I suppose might be zero length.

But I also wouldn't argue if we required this to be nonzero length.

-Ekr

> 2016-10-26 14:43 GMT+09:00 Eric Rescorla <ekr@rtfm.com>:
> > Folks,
> >
> > I have just posted draft-ietf-tls-tls13-18.
> >
> > The only wire format change from -17 is that I removed the extra key
> > derivation stage computing resumption_psk from RMS. This was a
> > holdover from when we also had a resumption context. Now PSK for
> > connection N+1 = RMS from connection N. Thanks to Kazuho for
> > suggesting this simplification.
> >
> > This draft also makes a number of minor editorial changes that
> > should make for easier reading.
> >
> > The two remaining open technical issues I am aware of are both
> > requirements issues:
> >
> > 1. Can you resume with a different SNI than the one that the
> >    connection was initiated with [current answer is "no"]?
> >
> > 2. Do you need an application profile to do post-handshake
> >    client auth [current answer is "no"]?
> >
> > There has been a bunch of discussion of these on the list but no
> > consensus declarations from the chairs. These are easy to change
> > in the draft once the chairs make the call.
> >
> > As always, comments welcome.
> >
> > -Ekr
> >
> > P.S. NSS will be skipping draft-17 and going right to -18. This
> > should happen before Seoul.
> >
> >
> > _______________________________________________
> > TLS mailing list
> > TLS@ietf.org
> > https://www.ietf.org/mailman/listinfo/tls
> >
>
>
>
> --
> Kazuho Oku
>