[OAUTH-WG] Clarification request on draft-ietf-oauth-v2-23#section-10.10

Nat Sakimura <sakimura@gmail.com> Thu, 02 February 2012 09:25 UTC

Return-Path: <sakimura@gmail.com>
X-Original-To: oauth@ietfa.amsl.com
Delivered-To: oauth@ietfa.amsl.com
Received: from localhost (localhost [127.0.0.1]) by ietfa.amsl.com (Postfix) with ESMTP id 5CD6721F8A55 for <oauth@ietfa.amsl.com>; Thu, 2 Feb 2012 01:25:12 -0800 (PST)
X-Virus-Scanned: amavisd-new at amsl.com
X-Spam-Flag: NO
X-Spam-Score: -3.599
X-Spam-Level:
X-Spam-Status: No, score=-3.599 tagged_above=-999 required=5 tests=[BAYES_00=-2.599, RCVD_IN_DNSWL_LOW=-1]
Received: from mail.ietf.org ([12.22.58.30]) by localhost (ietfa.amsl.com [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id 85ssJVC14Ro6 for <oauth@ietfa.amsl.com>; Thu, 2 Feb 2012 01:25:11 -0800 (PST)
Received: from mail-lpp01m010-f44.google.com (mail-lpp01m010-f44.google.com [209.85.215.44]) by ietfa.amsl.com (Postfix) with ESMTP id 4E3D721F8A27 for <oauth@ietf.org>; Thu, 2 Feb 2012 01:25:11 -0800 (PST)
Received: by lahl5 with SMTP id l5so1323062lah.31 for <oauth@ietf.org>; Thu, 02 Feb 2012 01:25:10 -0800 (PST)
DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=gamma; h=mime-version:date:message-id:subject:from:to:content-type; bh=v3iVZF23P8vTgVn7oUC7GPVTbrOqG/IX4JppwDSOyJw=; b=tvyZNxOvYG0Xza0xNcL+sv82auI8rdbNNeAnTcw0yuW2dgyN1OfW/kowt7qC3lSUO8 cdLFV08OcspJtU1jmF5nkpYIvmpZkOHVs6c8bGbD3LmkL6A2inVge89KnIcz/7Fe88GA KB8GO66mFrqmI2pkEidZ6yhOm/ES5c0ECzZEg=
MIME-Version: 1.0
Received: by 10.152.147.137 with SMTP id tk9mr1093946lab.8.1328174710237; Thu, 02 Feb 2012 01:25:10 -0800 (PST)
Received: by 10.152.21.133 with HTTP; Thu, 2 Feb 2012 01:25:10 -0800 (PST)
Date: Thu, 02 Feb 2012 18:25:10 +0900
Message-ID: <CABzCy2B4Dxb8BJe=Z5Sd_n8779JExj0u8n+xH8i9ypuFuwOJeg@mail.gmail.com>
From: Nat Sakimura <sakimura@gmail.com>
To: oauth <oauth@ietf.org>
Content-Type: text/plain; charset="ISO-8859-1"
Subject: [OAUTH-WG] Clarification request on draft-ietf-oauth-v2-23#section-10.10
X-BeenThere: oauth@ietf.org
X-Mailman-Version: 2.1.12
Precedence: list
List-Id: OAUTH WG <oauth.ietf.org>
List-Unsubscribe: <https://www.ietf.org/mailman/options/oauth>, <mailto:oauth-request@ietf.org?subject=unsubscribe>
List-Archive: <http://www.ietf.org/mail-archive/web/oauth>
List-Post: <mailto:oauth@ietf.org>
List-Help: <mailto:oauth-request@ietf.org?subject=help>
List-Subscribe: <https://www.ietf.org/mailman/listinfo/oauth>, <mailto:oauth-request@ietf.org?subject=subscribe>
X-List-Received-Date: Thu, 02 Feb 2012 09:25:12 -0000

hi.

The rev. 23 has a normative change in section 10.10 as:

10.10.  Credentials Guessing Attacks
  [...]
 Generated tokens and other credentials not intended for handling by
   end-users MUST be constructed from a cryptographically strong random
   or pseudo-random number sequence ([RFC1750]) generated by the
   authorization server.

Does this normative requirement only allows pseudo-random number
sequence described as in Section 6.3 of RFC1750?
Or does it allow something that includes it? I gather that it is the later,
but the wording "constructed from" sounds a little vague.

It also states:

 The probability of any two values being
   identical MUST be less than or equal to 2^(-128) and SHOULD be less
   than or equal to 2^(-160).

It is "the probability that a randomly generated guessed value being
identical to
the authoritatively generated token or credential value", I suppose.

--
Nat Sakimura (=nat)
Chairman, OpenID Foundation
http://nat.sakimura.org/
@_nat_en