Re: [TLS] Zero-RTT Data & PSK

Eric Rescorla <ekr@rtfm.com> Mon, 10 October 2016 22:00 UTC

Return-Path: <ekr@rtfm.com>
X-Original-To: tls@ietfa.amsl.com
Delivered-To: tls@ietfa.amsl.com
Received: from localhost (localhost [127.0.0.1]) by ietfa.amsl.com (Postfix) with ESMTP id 8CF9512979A for <tls@ietfa.amsl.com>; Mon, 10 Oct 2016 15:00:00 -0700 (PDT)
X-Virus-Scanned: amavisd-new at amsl.com
X-Spam-Flag: NO
X-Spam-Score: -2.599
X-Spam-Level:
X-Spam-Status: No, score=-2.599 tagged_above=-999 required=5 tests=[BAYES_00=-1.9, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, HTML_MESSAGE=0.001, RCVD_IN_DNSWL_LOW=-0.7] autolearn=ham autolearn_force=no
Authentication-Results: ietfa.amsl.com (amavisd-new); dkim=pass (2048-bit key) header.d=rtfm-com.20150623.gappssmtp.com
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 Sc7mP6bPkOZZ for <tls@ietfa.amsl.com>; Mon, 10 Oct 2016 14:59:59 -0700 (PDT)
Received: from mail-yw0-x231.google.com (mail-yw0-x231.google.com [IPv6:2607:f8b0:4002:c05::231]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by ietfa.amsl.com (Postfix) with ESMTPS id 179B2129786 for <tls@ietf.org>; Mon, 10 Oct 2016 14:59:59 -0700 (PDT)
Received: by mail-yw0-x231.google.com with SMTP id w3so1808333ywg.1 for <tls@ietf.org>; Mon, 10 Oct 2016 14:59:59 -0700 (PDT)
DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=rtfm-com.20150623.gappssmtp.com; s=20150623; h=mime-version:in-reply-to:references:from:date:message-id:subject:to :cc; bh=Q3PASbBQzl9D0AzWm+j7KPlTzIR+LQPBt8bSEuW7XWk=; b=elRpRat4kkP9neFjulMwfxDNoa7vnC6lCSoqWGgzJznbQixN/ZKmcmMHhEAkShXaYu 6DfBfzcQUS2dhEvTGllFW6birGWWUeXwou4zRzLj/9cKFyrTOwUFsyZFSplQZNz3qfRI 0VUZEqKZFPSIhQ+fKaUfIOK28Ya2XCV/l4HgfoJghTNIZR/4Z7xa6JZyBsq6hHR/huXw LJyYCJ7Qo97vyJqjTu5Wl9XwlsSoeYZOQU1Bg1UORgF8NDb5vYrw7w3FclvAWeTmKNvU 2TwTUWkpWfVZYtS6HYV9RxAEAL7ChXJ7CAbUNzmSLC7JiLZZbzGxS5mDttNy7rzHzd20 AywQ==
X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20130820; h=x-gm-message-state:mime-version:in-reply-to:references:from:date :message-id:subject:to:cc; bh=Q3PASbBQzl9D0AzWm+j7KPlTzIR+LQPBt8bSEuW7XWk=; b=FeG97b5TCG23Lgs/6xhbJ/fyzkLJW/j05f5q/SEfEhIKUBIh+BP6VXI1IYwI6NqzKA RsWuacKudGEgAHo1T9+tEs3JK74oqYQVcWiMQ9bGdLYvIdyFGVDtYADZS6RDgd4mykJd NkLtggrF8/q4XQVnkDNOsAvXnC6QQawGtXWeNDXyJPaW7JcrmLK+vU5Op0kpZY2PzWdW 5tKF407wZvPYup74RihLgXVbAGRv9RI6+16UmhiNnOLmRPWQrp0cK7mcawfUz4o8ljKv ZYPn0pOo70Ouq5TUfZ08c4g0X+xKfF+bvrEiPK2XVNSDtcTqdhiFvkewqunjxg05uquq ZKmw==
X-Gm-Message-State: AA6/9RmG9WCIxb37kQ09f+wFN/lvrpn38Wm4ys+aEAWi+G4jj0RoOJPuaeIAqvuTzayy8QkXAAnnx+u4qkAXZQ==
X-Received: by 10.129.83.134 with SMTP id h128mr426978ywb.52.1476136798315; Mon, 10 Oct 2016 14:59:58 -0700 (PDT)
MIME-Version: 1.0
Received: by 10.129.75.212 with HTTP; Mon, 10 Oct 2016 14:59:17 -0700 (PDT)
In-Reply-To: <CABkgnnXfB=t+6yTCk9hSoLg9BDZS-hv4pUQHB0xh-x09xNsNYQ@mail.gmail.com>
References: <2b155eb4-3268-c687-031e-6ac9928940c3@gmx.net> <CABkgnnXfB=t+6yTCk9hSoLg9BDZS-hv4pUQHB0xh-x09xNsNYQ@mail.gmail.com>
From: Eric Rescorla <ekr@rtfm.com>
Date: Mon, 10 Oct 2016 14:59:17 -0700
Message-ID: <CABcZeBPfEtNiviH+4fS8amnChjFWqgWnMDqY+1E=H0KTgkFrEQ@mail.gmail.com>
To: Martin Thomson <martin.thomson@gmail.com>
Content-Type: multipart/alternative; boundary="001a114e8108813ca9053e89e131"
Archived-At: <https://mailarchive.ietf.org/arch/msg/tls/MugSGJGrX4OqB3AP2Fya_egaBLk>
Cc: "<tls@ietf.org>" <tls@ietf.org>
Subject: Re: [TLS] Zero-RTT Data & PSK
X-BeenThere: tls@ietf.org
X-Mailman-Version: 2.1.17
Precedence: list
List-Id: "This is the mailing list for the Transport Layer Security working group of the IETF." <tls.ietf.org>
List-Unsubscribe: <https://www.ietf.org/mailman/options/tls>, <mailto:tls-request@ietf.org?subject=unsubscribe>
List-Archive: <https://mailarchive.ietf.org/arch/browse/tls/>
List-Post: <mailto:tls@ietf.org>
List-Help: <mailto:tls-request@ietf.org?subject=help>
List-Subscribe: <https://www.ietf.org/mailman/listinfo/tls>, <mailto:tls-request@ietf.org?subject=subscribe>
X-List-Received-Date: Mon, 10 Oct 2016 22:00:00 -0000

I agree with MT. Hannes, if you want to clean up the text to take into
account MT's comments, I will merge

On Sat, Sep 10, 2016 at 3:35 AM, Martin Thomson <martin.thomson@gmail.com>
wrote:

> On 9 September 2016 at 23:37, Hannes Tschofenig
> <hannes.tschofenig@gmx.net> wrote:
> > I am wondering why I cannot use Zero-RTT with just PSK-based
> authentication
> > (without a prior ticket change).
>
> I think that you would need to bind more things to the key in that
> case, but I assume that it would be OK if you did so.  You already
> need to pair a PSK with a hash, but if you paired it with a whole
> cipher suite instead and also the ALPN (which could be null), then I
> see no reason not to permit 0-RTT for pure PSK.  (I think that cipher
> suite + ALPN is sufficient, but someone can correct me if I missed
> anything.)
>
> _______________________________________________
> TLS mailing list
> TLS@ietf.org
> https://www.ietf.org/mailman/listinfo/tls
>