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<div class="moz-cite-prefix">On 21/9/2021 6:02 μ.μ., Corey Bonnell
wrote:<br>
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<p class="MsoNormal">Hi Dimitris,<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">> If the CA already knows that the
Subscriber Private Key was compromised and malicious code was
signed at a certain date in the past, we should allow the CRL
to contain that agreed revocation date without requiring a
first CRL and then a "subsequent" CRL entry.<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">Agreed, that is the intent. In addition to
the case you mentioned, I also am attempting to address the
case where a certificate is revoked (and CRLs/OCSP responses
have already been published denoting the revoked status) but
later it is discovered that the certificate should be
considered to be invalid starting from a different time. In
this case, the CA should be able to change the revocationDate
in subsequently published CRLs/OCSP responses to convey the
new date.<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">I tweaked the wording as follows (made some
changes to the existing third paragraph of 13.2.1 as well the
new fourth paragraph):<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal" style="margin-bottom:11.0pt"><span
style="font-family:"Cambria",serif;mso-fareast-language:EN-US">“A
Certificate MAY have a one-to-one relationship or
one-to-many relationship with the signed Code. Regardless,
revocation of a Certificate may invalidate the Code
Signatures on all signed Code, some of which could be
perfectly sound. Because of this, the CA MAY specify the
time at which the Certificate is first considered to be
invalid in the revocationDate field of a CRL entry or the
revocationTime field of a OCSP response to time-bind the set
of software affected by the revocation, and software should
continue to treat objects containing a timestamp dated
before the revocation date as valid.<o:p></o:p></span></p>
<p class="MsoNormal" style="margin-bottom:11.0pt"><span
style="font-family:"Cambria",serif;mso-fareast-language:EN-US">If
a Code Signing Certificate previously has been revoked, and
the CA later becomes aware of a more appropriate revocation
date, then the CA MAY use that revocation date in subsequent
CRL entries and OCSP responses for that Code Signing
Certificate.<o:p></o:p></span></p>
<p class="MsoNormal" style="margin-bottom:11.0pt"><span
style="font-family:"Cambria",serif;mso-fareast-language:EN-US">Effective
2022-02-01, if the CA includes the Invalidity Date CRL entry
extension in a CRL entry for a Code Signing Certificate,
then the time encoded in the Invalidity Date CRL extension
SHALL be equal to the time encoded in the revocationDate
field of the CRL entry.”<o:p></o:p></span></p>
<p class="MsoNormal">Does this revised wording help to clarify?</p>
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<br>
Yes, this is more clear, thank you.<br>
<br>
Dimitris.<br>
<blockquote type="cite"
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<p class="MsoNormal"><o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">Thanks,<o:p></o:p></p>
<p class="MsoNormal">Corey<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<div>
<div style="border:none;border-top:solid #E1E1E1
1.0pt;padding:3.0pt 0in 0in 0in">
<p class="MsoNormal"><b>From:</b> Dimitris Zacharopoulos
(HARICA) <a class="moz-txt-link-rfc2396E" href="mailto:dzacharo@harica.gr"><dzacharo@harica.gr></a> <br>
<b>Sent:</b> Tuesday, September 21, 2021 2:01 AM<br>
<b>To:</b> Corey Bonnell
<a class="moz-txt-link-rfc2396E" href="mailto:Corey.Bonnell@digicert.com"><Corey.Bonnell@digicert.com></a>;
<a class="moz-txt-link-abbreviated" href="mailto:cscwg-public@cabforum.org">cscwg-public@cabforum.org</a><br>
<b>Subject:</b> Re: [Cscwg-public] CRL Revocation Date
Clarification Pre-Ballot<o:p></o:p></p>
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</div>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal" style="margin-bottom:12.0pt">Hi Corey,<br>
<br>
If the CA already knows that the Subscriber Private Key was
compromised and malicious code was signed at a certain date in
the past, we should allow the CRL to contain that agreed
revocation date without requiring a first CRL and then a
"subsequent" CRL entry.<br>
<br>
<br>
Thanks,<br>
Dimitris.<o:p></o:p></p>
<div>
<p class="MsoNormal">On 20/9/2021 7:52 μ.μ., Corey Bonnell via
Cscwg-public wrote:<o:p></o:p></p>
</div>
<blockquote style="margin-top:5.0pt;margin-bottom:5.0pt">
<p class="MsoNormal">Hello,<o:p></o:p></p>
<p class="MsoNormal">As discussed last week, it would be
valuable to ensure that there is clarity regarding how
revocation/invalidity dates are encoded in CRLs so that
relying party software can make the correct trust decisions
regarding compromised code. Attached is a small change to
13.2.1 to reflect that the revocationDate CRL entry field
shall be used to denote when a certificate is invalid. The
proposed language allows for the Invalidity Date CRL entry
extension to continue to appear, but the time encoded in it
must be the same as the revocationDate for the entry. I
don’t believe this causes issues with Windows CRL
processing, please let me know if it does and I’ll remove
the provision.<o:p></o:p></p>
<p class="MsoNormal"> <o:p></o:p></p>
<p class="MsoNormal">For reference, here are the two proposed
paragraphs to be added to 13.2.1:<o:p></o:p></p>
<p class="MsoNormal"> <o:p></o:p></p>
<p class="MsoNormal"><span
style="font-size:10.0pt;font-family:"Courier
New"">If a Code Signing Certificate is revoked, and
the CA later becomes aware of a more appropriate
revocation date, then the CA MAY use that revocation date
in subsequent CRL entries and OCSP responses for that Code
Signing Certificate.</span><o:p></o:p></p>
<p class="MsoNormal"><span
style="font-size:10.0pt;font-family:"Courier
New""> </span><o:p></o:p></p>
<p class="MsoNormal"><span
style="font-size:10.0pt;font-family:"Courier
New"">Effective 2022-02-01, if the CA includes the
Invalidity Date CRL entry extension in a CRL entry for a
Code Signing Certificate, then the time encoded in the
Invalidity Date CRL extension SHALL be equal to the time
encoded in the revocationDate field of the CRL entry.</span><o:p></o:p></p>
<p class="MsoNormal"> <o:p></o:p></p>
<p class="MsoNormal">Given that the revocation date is
potentially security sensitive, I think it’s worthwhile to
get this clarified prior to the RFC 3647/Pandoc effort. In
addition to comments/questions on the proposed language,
we’re looking for two endorsers.<o:p></o:p></p>
<p class="MsoNormal"> <o:p></o:p></p>
<p class="MsoNormal">Thanks,<o:p></o:p></p>
<p class="MsoNormal">Corey<o:p></o:p></p>
<p class="MsoNormal"><br>
<br>
<o:p></o:p></p>
<pre>_______________________________________________<o:p></o:p></pre>
<pre>Cscwg-public mailing list<o:p></o:p></pre>
<pre><a href="mailto:Cscwg-public@cabforum.org" moz-do-not-send="true">Cscwg-public@cabforum.org</a><o:p></o:p></pre>
<pre><a href="https://lists.cabforum.org/mailman/listinfo/cscwg-public" moz-do-not-send="true">https://lists.cabforum.org/mailman/listinfo/cscwg-public</a><o:p></o:p></pre>
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<p class="MsoNormal"><o:p> </o:p></p>
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