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Hi Martijn,<br>
<br>
Two suggestions submitted on GitHub.<br>
<br>
Regarding the prohibition of restoring a private key of a Timestamp
Certificate, I'm not sure how universal this can be because some
HSMs restore an entire slot/partition, which might contain Private
Keys associated with obsolete Timestamp Certificates. As the ballot
is written, such an action would be a violation.<br>
<br>
In general, a "key destruction" ceremony includes the deletion of
all copies of the key, including copies that reside in backups. If
we require a "key destruction" ceremony, the "restore key" case is
nonsensical. We probably need to work on this some more so that we
all have the same understanding and expectations.<br>
<br>
Let me restate the intent of this requirement as discussed all this
time, and please correct me if I'm wrong.<br>
<br>
IMO, the goal is to put the keys associated with Timestamp
Certificates out of use, 15 months after the <i>notBefore </i>of
the Timestamp Certificate. <br>
<br>
In order to achieve some level of assurance for this action, the
proposal is to delete the keys from the HSM 18 months after the <i>notBefore
</i>of the Timestamp Certificate, in an audited way, witnessed by
members of two different Trusted Roles (not by two Trusted Role
Members, i.e. you can't use two persons of the same Trusted Role). <br>
<br>
It's ok to keep the keys in backups but if you happen to restore
them in an HSM, you must not use them to sign anything. If a CA/TSA
can also "destroy" the key, meaning that all copies of that private
key can be unequivocally/securely deleted (i.e. without a way to
recover the key), including any instance of the key as part of a
backup, the better!<br>
<br>
Thoughts?<br>
<br>
Dimitris.<br>
<br>
<br>
<div class="moz-cite-prefix">On 6/3/2024 2:07 μ.μ., Martijn
Katerbarg via Cscwg-public wrote:<br>
</div>
<blockquote type="cite"
cite="mid:0100018e13a9bd97-d838febe-f003-42df-94c9-2f7301aff0d0-000000@email.amazonses.com">
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<p class="MsoNormal"><span lang="EN-US">All,<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US"><o:p> </o:p></span></p>
<p class="MsoNormal"><span lang="EN-US">As discussed last week,
I’d send out the draft language for this ballot once more
before starting the discussion period. The latest version
can be found in <a
href="https://github.com/cabforum/code-signing/pull/34"
moz-do-not-send="true" class="moz-txt-link-freetext">https://github.com/cabforum/code-signing/pull/34</a><o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US"><o:p> </o:p></span></p>
<p class="MsoNormal"><span lang="EN-US">I’ve made changes this
morning to add 3 effective dates, these are:<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US"><o:p> </o:p></span></p>
<ul style="margin-top:0cm" type="disc">
<li class="MsoListParagraph"
style="margin-left:0cm;mso-list:l1 level1 lfo4"><span
lang="EN-US">For the removal of private keys associated
with timestamp certificates, effective June 1<sup>st</sup>,
2024, CAs will need to properly log the removal of said
key. <o:p></o:p></span></li>
<ul style="margin-top:0cm" type="circle">
<li class="MsoListParagraph"
style="margin-left:0cm;mso-list:l1 level2 lfo4"><span
lang="EN-US">While I expect CAs to already properly log
this for audit purposes even now, there may be
exceptions for when this has not been done, for example
a private key or timestamp certificate that was signed
maybe 20 years ago. This language is added to avoid any
confusion on from what point there needs to be an audit
trail<o:p></o:p></span></li>
</ul>
<li class="MsoListParagraph"
style="margin-left:0cm;mso-list:l1 level1 lfo4"><span
lang="EN-US">Effective April 15, 2025, private keys
associated with SubCAs containing the “Time Stamping” EKU
will need to be placed in offline HSMs.<o:p></o:p></span></li>
<ul style="margin-top:0cm" type="circle">
<li class="MsoListParagraph"
style="margin-left:0cm;mso-list:l1 level2 lfo4"><span
lang="EN-US">I believe a roughly one year effective date
is appropriate here, since CAs may need to move keys
from one HSM to another.<o:p></o:p></span></li>
</ul>
<li class="MsoListParagraph"
style="margin-left:0cm;mso-list:l1 level1 lfo4"><span
lang="EN-US">For private keys associated with timestamp
certificates that were issued for greater than 15 months,
CAs will need to remove the private keys 18 months after
certificate issuance, starting April 15, 2025.<o:p></o:p></span></li>
<ul style="margin-top:0cm" type="circle">
<li class="MsoListParagraph"
style="margin-left:0cm;mso-list:l1 level2 lfo4"><span
lang="EN-US">Likewise, I feel like anything involving
HSM process changes, should have a longer effective
date, and it makes sense to align this with the
effective date above.<o:p></o:p></span></li>
</ul>
</ul>
<p class="MsoNormal"><span lang="EN-US"><o:p> </o:p></span></p>
<p class="MsoNormal"><span lang="EN-US">I’ll start a ballot on
this early next week, unless there is concern with the
above. <o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US"><o:p> </o:p></span></p>
<p class="MsoNormal"><span lang="EN-US">Regards,<br>
<br>
Martijn<o:p></o:p></span></p>
</div>
<br>
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