IETF Logo Mail Archive

Re: [TLS] Pre-master secret formatting for master secret calculation with DH in TLS 1.x

Jack Lloyd <lloyd@randombit.net> Fri, 08 February 2013 19:23 UTC

Return-Path: <lloyd@randombit.net>
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 4B9C321F8BC9 for <tls@ietfa.amsl.com>; Fri, 8 Feb 2013 11:23:04 -0800 (PST)
X-Virus-Scanned: amavisd-new at amsl.com
X-Spam-Flag: NO
X-Spam-Score: -3.265
X-Spam-Level:
X-Spam-Status: No, score=-3.265 tagged_above=-999 required=5 tests=[BAYES_00=-2.599, IP_NOT_FRIENDLY=0.334, RCVD_IN_DNSWL_LOW=-1]
Received: from mail.ietf.org ([64.170.98.30]) by localhost (ietfa.amsl.com [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id dBVRM5tQDyvN for <tls@ietfa.amsl.com>; Fri, 8 Feb 2013 11:23:01 -0800 (PST)
Received: from chihiro.randombit.net (chihiro.randombit.net [69.48.226.76]) by ietfa.amsl.com (Postfix) with ESMTP id 9CF8721F8BE7 for <tls@ietf.org>; Fri, 8 Feb 2013 11:23:01 -0800 (PST)
Received: by chihiro.randombit.net (Postfix, from userid 1000) id 034C41249AF0; Fri, 8 Feb 2013 14:22:59 -0500 (EST)
Date: Fri, 08 Feb 2013 14:22:59 -0500
From: Jack Lloyd <lloyd@randombit.net>
To: tls@ietf.org
Message-ID: <20130208192259.GA31819@randombit.net>
Mail-Followup-To: tls@ietf.org
References: <51154DCF.4090407@brainhub.org>
MIME-Version: 1.0
Content-Type: text/plain; charset="us-ascii"
Content-Disposition: inline
In-Reply-To: <51154DCF.4090407@brainhub.org>
X-PGP-Fingerprint: 3F69 2E64 6D92 3BBE E7AE 9258 5C0F 96E8 4EC1 6D6B
X-PGP-Key: http://www.randombit.net/pgpkey.html
User-Agent: Mutt/1.5.21 (2010-09-15)
Subject: Re: [TLS] Pre-master secret formatting for master secret calculation with DH in TLS 1.x
X-BeenThere: tls@ietf.org
X-Mailman-Version: 2.1.12
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: <http://www.ietf.org/mail-archive/web/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: Fri, 08 Feb 2013 19:23:05 -0000

On Fri, Feb 08, 2013 at 11:11:11AM -0800, Andrey Jivsov wrote:
> I ran into an interoperability problem between our TLS implementation 
> and another very popular one.
> 
> The question is what exactly is the formatting  for the RFC224 sec. 
> 8.1.2 "Diffie-Hellman" shared secret 'Z' ?

Both TLS 1.1 and 1.2 RFCs say in this section "Leading bytes of Z that
contain all zero bits are stripped before it is used as the
pre_master_secret." and it is my understanding that while left
unstated, this is also the case for SSLv3/TLS 1.0 DH.

-Jack

v2.23.0 | Report a Bug | By Email