Re: [TLS] Consensus for AEAD IV

Russ Housley <housley@vigilsec.com> Fri, 24 April 2015 21:01 UTC

Return-Path: <housley@vigilsec.com>
X-Original-To: tls@ietfa.amsl.com
Delivered-To: tls@ietfa.amsl.com
Received: from localhost (ietfa.amsl.com [127.0.0.1]) by ietfa.amsl.com (Postfix) with ESMTP id 057901A92FD for <tls@ietfa.amsl.com>; Fri, 24 Apr 2015 14:01:11 -0700 (PDT)
X-Virus-Scanned: amavisd-new at amsl.com
X-Spam-Flag: NO
X-Spam-Score: -101.899
X-Spam-Level:
X-Spam-Status: No, score=-101.899 tagged_above=-999 required=5 tests=[BAYES_00=-1.9, HTML_MESSAGE=0.001, USER_IN_WHITELIST=-100] autolearn=ham
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 xY7ZR7FQiw8c for <tls@ietfa.amsl.com>; Fri, 24 Apr 2015 14:01:09 -0700 (PDT)
Received: from odin.smetech.net (x-bolt-wan.smeinc.net [209.135.219.146]) by ietfa.amsl.com (Postfix) with ESMTP id 5AE041A8A7E for <tls@ietf.org>; Fri, 24 Apr 2015 14:01:09 -0700 (PDT)
Received: from localhost (unknown [209.135.209.5]) by odin.smetech.net (Postfix) with ESMTP id A9E729A4020; Fri, 24 Apr 2015 17:00:58 -0400 (EDT)
X-Virus-Scanned: amavisd-new at smetech.net
Received: from odin.smetech.net ([209.135.209.4]) by localhost (ronin.smeinc.net [209.135.209.5]) (amavisd-new, port 10024) with ESMTP id 5+lm3LB-tHMP; Fri, 24 Apr 2015 17:00:37 -0400 (EDT)
Received: from [192.168.2.100] (pool-96-255-145-93.washdc.fios.verizon.net [96.255.145.93]) (using TLSv1 with cipher AES128-SHA (128/128 bits)) (No client certificate requested) by odin.smetech.net (Postfix) with ESMTP id B8EE19A400D; Fri, 24 Apr 2015 17:00:37 -0400 (EDT)
Mime-Version: 1.0 (Apple Message framework v1085)
Content-Type: multipart/alternative; boundary="Apple-Mail-65-630461104"
From: Russ Housley <housley@vigilsec.com>
In-Reply-To: <CAOgPGoDNuhmnNpZ7ELCfBHS4rKuj+3j1+YiuxLkST+z1J+tOKQ@mail.gmail.com>
Date: Fri, 24 Apr 2015 17:00:26 -0400
Message-Id: <6DF16074-2C87-416B-9C0D-0C7797984B5E@vigilsec.com>
References: <CAOgPGoC14uhjrZAQvDHFQrJoyoVNELpNNd4+Hh==zwf9ipyY5g@mail.gmail.com> <CABkgnnU50pvH+LFsN3BL9LfvYhZOxmJV1JYzODeC=-JpZSh8Lw@mail.gmail.com> <CAOgPGoDNuhmnNpZ7ELCfBHS4rKuj+3j1+YiuxLkST+z1J+tOKQ@mail.gmail.com>
To: Joseph Salowey <joe@salowey.net>
X-Mailer: Apple Mail (2.1085)
Archived-At: <http://mailarchive.ietf.org/arch/msg/tls/hqSOMc_d1K7JerJhlE8PXkJvW2s>
Cc: IETF TLS <tls@ietf.org>
Subject: Re: [TLS] Consensus for AEAD IV
X-BeenThere: tls@ietf.org
X-Mailman-Version: 2.1.15
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, 24 Apr 2015 21:01:11 -0000

Joe:

> On Fri, Apr 24, 2015 at 1:00 PM, Martin Thomson <martin.thomson@gmail.com> wrote:
> On 24 April 2015 at 10:10, Joseph Salowey <joe@salowey.net> wrote:
> > The general consensus on the list seems to prefer to derive "IV" and use it
> > to make the AEAD nonce less predictable. Most folks seemed to be OK with
> > this approach.    In Dallas, there was significant support for using the
> > derived "IV" as a per session XOR mask for the counter.  If you have
> > objections to this approach please respond on the list by May 1, 2015 .
> 
> 
> You aren't being particularly precise about the process here.
> 
> I believe that these were the two options that were most debated:
> 
> a)  nonce = zeroes(N_MIN) XOR counter
> b)  nonce = HKDF(...., N_MIN) XOR counter
> 
> Did you mean the latter option?
> 
> [Joe] Yes, the later where the quantity XORed with the counter is derived during the handshake.  

If the computation is done in an HSM-friendly fashion, I am supportive.

Russ