IETF Logo Mail Archive

Re: [kitten] [IANA #748877] please review SASL-SCRAM-256

Tony Hansen <tony@att.com> Fri, 11 April 2014 03:36 UTC

Return-Path: <tony@att.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 1AC701A041D for <kitten@ietfa.amsl.com>; Thu, 10 Apr 2014 20:36:04 -0700 (PDT)
X-Virus-Scanned: amavisd-new at amsl.com
X-Spam-Flag: NO
X-Spam-Score: -2.172
X-Spam-Level:
X-Spam-Status: No, score=-2.172 tagged_above=-999 required=5 tests=[BAYES_00=-1.9, RCVD_IN_DNSWL_NONE=-0.0001, RP_MATCHES_RCVD=-0.272] 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 4_7YOmA4YcjV for <kitten@ietfa.amsl.com>; Thu, 10 Apr 2014 20:35:59 -0700 (PDT)
Received: from egssmtp02.att.com (egssmtp02.att.com [144.160.128.166]) by ietfa.amsl.com (Postfix) with ESMTP id C96F21A0425 for <kitten@ietf.org>; Thu, 10 Apr 2014 20:24:26 -0700 (PDT)
Received: from mailgw1.maillennium.att.com (maillennium.att.com [135.25.114.99]) by egssmtp02.att.com ( EGS R6 8.14.5/8.14.5) with ESMTP id s3B3OPjt002671 for <kitten@ietf.org>; Thu, 10 Apr 2014 20:24:25 -0700
Received: from vpn-135-70-100-137.vpn.swst.att.com ([135.70.100.137]) by maillennium.att.com (mailgw1) with ESMTP id <20140411032420gw100j0chre>; Fri, 11 Apr 2014 03:24:25 +0000
X-Originating-IP: [135.70.100.137]
Message-ID: <53476066.3090206@att.com>
Date: Thu, 10 Apr 2014 23:24:22 -0400
From: Tony Hansen <tony@att.com>
User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.9; rv:24.0) Gecko/20100101 Thunderbird/24.4.0
MIME-Version: 1.0
To: kitten@ietf.org
References: <RT-Ticket-748877@icann.org> <5319DE8B.1030202@att.com> <rt-4.0.8-12541-1394569374-953.748877-9-0@icann.org> <20140312162849.152e924b@latte.josefsson.org> <20140411001759.3d89cfb5@latte.josefsson.org> <CAKHUCzxxbABfJDR8JZ5evHXFHmsBvqVdHTX0QLg4ONsqNKgk5g@mail.gmail.com> <53475A88.3060202@att.com> <87d2goa6xh.fsf@windlord.stanford.edu>
In-Reply-To: <87d2goa6xh.fsf@windlord.stanford.edu>
Content-Type: text/plain; charset="ISO-8859-1"; format="flowed"
Content-Transfer-Encoding: 7bit
Archived-At: http://mailarchive.ietf.org/arch/msg/kitten/sSSPHBk6AS6ek_C_fcS5DMjhHMc
Subject: Re: [kitten] [IANA #748877] please review SASL-SCRAM-256
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: Fri, 11 Apr 2014 03:36:04 -0000

On 4/10/14, 11:20 PM, Russ Allbery wrote:
> Tony Hansen <tony@att.com> writes:
>
>> OK, I figured it was worth trying to do it this way. I'll start the RFC
>> process.
>> Dave, a question for you: What do you think a better minimum iteration
>> count should be for SCRAM-SHA-256? Why should it be any different than
>> the value specified for SCRAM-SHA-1 (4096)?
> It might be worth considering increasing the minimum iteration count to
> something that takes appreciable time on modern hardware.  I've not tested
> SCRAM-SHA-256, but PBKDF2 with SHA-256 requires around 15,000 rounds to
> take 0.1 seconds on a typical desktop system.

On the other hand, we've found that 4096 is somewhat onerous and barely 
tolerable on most smart phones.

     Tony Hansen

v2.30.2 | Report a Bug | By Email | System Status