Re: [lamps] Renewing (short lived) certs with EST (RFC7030) [was: Re: Sean: Permissibility of expired cert renewal]

Michael Richardson <> Thu, 30 August 2018 14:43 UTC

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From: Michael Richardson <>
To: Sean Turner <>
cc: Toerless Eckert <>,,
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Date: Thu, 30 Aug 2018 10:43:09 -0400
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Subject: Re: [lamps] Renewing (short lived) certs with EST (RFC7030) [was: Re: Sean: Permissibility of expired cert renewal]
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Sean Turner <> wrote:
    >> Seems to leave 5280 as the existing doc standing in the way ?
    >> If so, how to most easily fix this ?

    > I think what you’re after is an explicit statement that says you’re
    > free to use an expired certificate to request a new certificate? If
    > you’re looking for that to be added to RFC 5280 I’d say good luck
    > because it’s policy specific thing.

I think that what we want to do is write a Security Considerations for
renewing certificates using EST with an expired certificate as
authentication.    We need to outline what kinds of policy might be required,
and when it would be approrpriate not to accept specific certificates, or
when it might be appropriate to accept no expired certificates (perhaps for an
interval of time).  Or just how old (as a percentage of cert life) is too

I think that the threat case here is that devices are inappropriately
disposed of (vulnerable to dumpster diving or ebay acquisition), with the
assumption that the credentials are old and do not need to be wiped.
Probably there are other threat cases that I have not thought of, and I think
that the goal would be to write the threats down... ideally to give them

Michael Richardson <>ca>, Sandelman Software Works
 -= IPv6 IoT consulting =-