[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

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Date: Thu, 02 Feb 2012 18:25:10 +0900
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From: Nat Sakimura <sakimura@gmail.com>
To: oauth <oauth@ietf.org>
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Subject: [OAUTH-WG] Clarification request on draft-ietf-oauth-v2-23#section-10.10
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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