IETF Logo Mail Archive

Re: [kitten] Kerberos extra round trips I-D revised

Nico Williams <nico@cryptonector.com> Wed, 12 November 2014 20:15 UTC

Return-Path: <nico@cryptonector.com>
X-Original-To: kitten@ietfa.amsl.com
Delivered-To: kitten@ietfa.amsl.com
Received: from localhost (ietfa.amsl.com [127.0.0.1]) by ietfa.amsl.com (Postfix) with ESMTP id F35CC1AD042 for <kitten@ietfa.amsl.com>; Wed, 12 Nov 2014 12:15:01 -0800 (PST)
X-Virus-Scanned: amavisd-new at amsl.com
X-Spam-Flag: NO
X-Spam-Score: -1.666
X-Spam-Level:
X-Spam-Status: No, score=-1.666 tagged_above=-999 required=5 tests=[BAYES_00=-1.9, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, IP_NOT_FRIENDLY=0.334, RCVD_IN_DNSWL_NONE=-0.0001] autolearn=no
Received: from mail.ietf.org ([4.31.198.44]) by localhost (ietfa.amsl.com [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id TBWeHs_W3Q13 for <kitten@ietfa.amsl.com>; Wed, 12 Nov 2014 12:15:01 -0800 (PST)
Received: from homiemail-a107.g.dreamhost.com (sub4.mail.dreamhost.com [69.163.253.135]) by ietfa.amsl.com (Postfix) with ESMTP id 006AA1AD272 for <kitten@ietf.org>; Wed, 12 Nov 2014 12:12:33 -0800 (PST)
Received: from homiemail-a107.g.dreamhost.com (localhost [127.0.0.1]) by homiemail-a107.g.dreamhost.com (Postfix) with ESMTP id C1BDA2007F109; Wed, 12 Nov 2014 12:12:33 -0800 (PST)
DKIM-Signature: v=1; a=rsa-sha1; c=relaxed; d=cryptonector.com; h=date :from:to:cc:subject:message-id:references:mime-version :content-type:in-reply-to; s=cryptonector.com; bh=MdawJtBa1aP0ZK 0/wtUTNBJbiR4=; b=qA/jwEzTxxqB26j5KddJCpfd4OygUyISIohy4hzhdvNraT KVu7nhL8nyc4uj24GY8zrjkeuFQvqfgqYKlP4K1VbWGiB7VcoQptq5bCWpzJkuQ1 xPTBomG+8bNhUWgsTJ5Xi9xvEBJVJ73ZHR3DuroNXMP9B881rfH7pK5JR6Z+s=
Received: from localhost (108-207-244-174.lightspeed.austtx.sbcglobal.net [108.207.244.174]) (Authenticated sender: nico@cryptonector.com) by homiemail-a107.g.dreamhost.com (Postfix) with ESMTPA id 77DE12007F10B; Wed, 12 Nov 2014 12:12:33 -0800 (PST)
Date: Wed, 12 Nov 2014 14:12:33 -0600
From: Nico Williams <nico@cryptonector.com>
To: Greg Hudson <ghudson@mit.edu>
Message-ID: <20141112201231.GB3124@localhost>
References: <20141027071704.GC14215@localhost> <alpine.GSO.1.10.1411071543280.27826@multics.mit.edu> <54624E87.8010007@mit.edu> <20141111185423.GM3412@localhost> <54638C46.8060203@mit.edu> <20141112200552.GA3124@localhost>
MIME-Version: 1.0
Content-Type: text/plain; charset="us-ascii"
Content-Disposition: inline
In-Reply-To: <20141112200552.GA3124@localhost>
User-Agent: Mutt/1.5.21 (2010-09-15)
Archived-At: http://mailarchive.ietf.org/arch/msg/kitten/xThw0XQzsDYPDYewfK71x2KOpO4
Cc: kitten@ietf.org
Subject: Re: [kitten] Kerberos extra round trips I-D revised
X-BeenThere: kitten@ietf.org
X-Mailman-Version: 2.1.15
Precedence: list
List-Id: Common Authentication Technologies - Next Generation <kitten.ietf.org>
List-Unsubscribe: <https://www.ietf.org/mailman/options/kitten>, <mailto:kitten-request@ietf.org?subject=unsubscribe>
List-Archive: <http://www.ietf.org/mail-archive/web/kitten/>
List-Post: <mailto:kitten@ietf.org>
List-Help: <mailto:kitten-request@ietf.org?subject=help>
List-Subscribe: <https://www.ietf.org/mailman/listinfo/kitten>, <mailto:kitten-request@ietf.org?subject=subscribe>
X-List-Received-Date: Wed, 12 Nov 2014 20:15:02 -0000

On Wed, Nov 12, 2014 at 02:05:54PM -0600, Nico Williams wrote:
> The kDH flows might look like this:
> 
>  - 2-token flow (optimistic negotiation succeeds, no acceptor key
>    confimation):

I should explain that in this case the acceptor does confirm the non-kDH
symmetric sub-session key, but not the DH shared secret.  I think that's
a reasonable approach.

>  - 4-token flow (optimistic negotiation fails, acceptor key confirmation
>    desired):

And here I screwed up, there's no need for a fourth token because the
acceptor does confirm the non-kDH symmetric sub-session key, which is
good enough.

However, maybe we do need to confirm the DH shared secret?  I hope not.

Nico
--

v2.23.0 | Report a Bug | By Email