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Re: [pkix] A non-compliant use of the EKU extension in Mozilla's CA Certificate Policy Version 2.1.

Stephen Kent <kent@bbn.com> Tue, 19 February 2013 20:29 UTC

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Date: Tue, 19 Feb 2013 15:29:59 -0500
From: Stephen Kent <kent@bbn.com>
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To: Denis Pinkas <denis.pinkas@bull.net>, pkix <pkix@ietf.org>
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Subject: Re: [pkix] A non-compliant use of the EKU extension in Mozilla's CA Certificate Policy Version 2.1.
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Denis,

I agree with your analysis of the situation, as seconded by David Cooper.

I think it unfortunate that Mozilla is advising folks to use EKU in a 
fashion that is not supported
by X.509 or 5280. (Specifically, a compliant RP should not reject a 
subordinate cert based on an EKU value
encountered in a CA cert higher in a cert path.)

While I appreciate the desire to have this sort of transitive scoping 
expressed via an EKU,
that extension, unlike some others in X.509/5280, does not offer this 
feature.  It would be
preferable to define a nee extension, rather that misinterpret an 
existing one.

Sorry, Stefan, but just because MS earlier did this doesn't make it 
right :-).

Steve

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