Re: [secdir] Secdir last call review of draft-ietf-lamps-hash-of-root-key-cert-extn-03

Russ Housley <> Tue, 08 January 2019 17:40 UTC

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From: Russ Housley <>
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Date: Tue, 8 Jan 2019 12:33:45 -0500
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To: Adam Montville <>
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Subject: Re: [secdir] Secdir last call review of draft-ietf-lamps-hash-of-root-key-cert-extn-03
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> On Jan 8, 2019, at 9:16 AM, Adam Montville <> wrote:
> Reviewer: Adam Montville
> Review result: Ready
> This draft is ready. It's a clever (though not foolproof) way to prime the pump
> for root certificate updates. I'm not an ASN.1 expert, so I can't really opine
> on the structure in Section 3, but from what I can tell it looks sane.
> Operational considerations seems sane. Security considerations rely on those
> from RFC5280, and additionally addresses: 1) analysis before the
> next-generation root certificate is released, 2) key strength considerations
> (equal or greater than current), 3) unforeseen cryptoanalytic advances, 4)
> typical hash pre-image attacks, and 5) early release of the next-generation
> public key.
> One area in the security considerations that could be enhanced is the
> recommended action to take in the case of an early next-generation public key
> release. The language in the draft states: "The second transition occurs when
> the Root CA is confident that the population of relying parties have completed
> the first transition, and it takes the Root CA to the freshly generated key
> pair." The question that came to mind was: What might bring about such
> confidence? I'm not sure that it's possible to generalize an answer to that
> question, however.


Thanks for the review.

I can assure you that I compiled the ASN.1 module.

This paragraph is the result of the discussion in the LAMPS WG session in London.  The timing is not that critical if the oldWithNew and newWithOld advice from RFC 2510 (updated to RFC 4210) is followed.  This is talked about in Section 5 on "Operational Considerations".  I have an update to the paragraph in Section 5 based on other comments:

   Guidance on the transition from one trust anchor to another is
   available in Section 4.4 of [RFC4210].  In particular, the oldWithNew
   and newWithOld advice ensures that relying parties are able to
   validate certificates issued under the current Root CA certificate
   and the next generation Root CA certificate throughout the
   transition.  Further, this advice avoids the need for all relying
   parties to make the transition at the same time.