Re: [pkix] Managing Long-Lived CA certs

"Erik Andersen" <> Tue, 18 July 2017 15:48 UTC

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From: "Erik Andersen" <>
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Date: Tue, 18 Jul 2017 17:47:50 +0200
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Subject: Re: [pkix] Managing Long-Lived CA certs
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Hi David,


PKIX is not the whole world.


The smart grid security work within IEC TC57 WG15 does not refer to RFC 5280, but only to X.509. X.509 provides functionality, like authorization and validation lists (AVLs) not part  of any IETF specification.


In the smart grid and IoT world, traditional PKI techniques fall short. I believe that is what Max is trying to tell.




Fra: pkix [] På vegne af David A. Cooper
Sendt: 18 July 2017 16:03
Til: Peter Gutmann <>
Cc: PKIX <>
Emne: Re: [pkix] Managing Long-Lived CA certs


Can you provide a citation for your claim that "PKIX says you're not allowed to use it. No reason given, you just can't."?

RFC 5280 says:

This specification obsoletes [RFC3280].  Differences from RFC 3280 are summarized below:

      * Section in RFC 3280, which specified the
        privateKeyUsagePeriod certificate extension but deprecated its
        use, was removed.  Use of this ISO standard extension is neither
        deprecated nor recommended for use in the Internet PKI.

"Use of this ISO standard extension is neither deprecated nor recommended" doesn't sound like "you just can't" to me.

On 07/17/2017 11:31 PM, Peter Gutmann wrote:

Erik Andersen  <> <> writes:

What about the private key usage period extension

That would be the obvious choice, but PKIX says you're not allowed to use it.
No reason given, you just can't.  This would imply that support for it in
implementations is going to be hard to find...