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<p class="MsoNormal"><span style="color:#1F497D">Forwarding for Ben Nick since it didn’t reach the entire forum.<o:p></o:p></span></p>
<p class="MsoNormal"><a name="_MailEndCompose"><span style="color:#1F497D"><o:p> </o:p></span></a></p>
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<p class="MsoNormal"><b><span style="font-size:10.0pt;font-family:"Tahoma","sans-serif"">From:</span></b><span style="font-size:10.0pt;font-family:"Tahoma","sans-serif""> Ben Nick [mailto:bnick@microsoft.com]
<br>
<b>Sent:</b> Friday, October 24, 2014 12:39 PM<br>
<b>To:</b> Bruce Morton; Ben Wilson; Rick Andrews; Jeremy Rowley; CABFPub<br>
<b>Subject:</b> RE: Private key control<o:p></o:p></span></p>
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<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal"><span style="color:#1F497D">From a technical standpoint, I believe Bruce is correct. As this check alone does not authenticate the owner of the key, it does not mitigate against MITM or tampering attacks on the CSR.
<o:p></o:p></span></p>
<p class="MsoNormal"><span style="color:#1F497D"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="color:#1F497D">There may be some procedural value in preventing subscribers from accidentally listing a public key in a CSR when the subscriber does not control the corresponding private key. If CAs do not believe that this
provides significant benefit, it makes sense to drop this requirement.<o:p></o:p></span></p>
<p class="MsoNormal"><span style="color:#1F497D"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="color:#1F497D">Ben Nick<o:p></o:p></span></p>
<p class="MsoNormal"><span style="color:#1F497D"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="color:#1F497D"><o:p> </o:p></span></p>
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<p class="MsoNormal"><b>From:</b> <a href="mailto:public-bounces@cabforum.org">public-bounces@cabforum.org</a> [<a href="mailto:public-bounces@cabforum.org">mailto:public-bounces@cabforum.org</a>]
<b>On Behalf Of </b>Bruce Morton<br>
<b>Sent:</b> Friday, October 24, 2014 10:14 AM<br>
<b>To:</b> Ben Wilson; Rick Andrews; Jeremy Rowley; CABFPub<br>
<b>Subject:</b> Re: [cabfpub] Private key control<o:p></o:p></p>
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<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal"><span style="color:#1F497D">Ben,<o:p></o:p></span></p>
<p class="MsoNormal"><span style="color:#1F497D"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="color:#1F497D">I do not believe that we technically validate private key control. Obtaining a CSR does not verify the control of the private key. You would need to compare the signature on the CSR to something.<o:p></o:p></span></p>
<p class="MsoNormal"><span style="color:#1F497D"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="color:#1F497D">I think what all CAs do is receive authorization to issue a certificate for a certain domain. We receive authorization by contacting the applicant, the domain owner, or accepting a two-factor authorization.<o:p></o:p></span></p>
<p class="MsoNormal"><span style="color:#1F497D"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="color:#1F497D">So I would suggest that we either use some wording about authorization or put in No Stipulation. I do not believe that addressing this requirement covers any policy that has been provided from a browser.<o:p></o:p></span></p>
<p class="MsoNormal"><span style="color:#1F497D"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="color:#1F497D">Bruce.<o:p></o:p></span></p>
<p class="MsoNormal"><span style="color:#1F497D"><o:p> </o:p></span></p>
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<p class="MsoNormal"><b>From:</b> Ben Wilson [<a href="mailto:ben.wilson@digicert.com">mailto:ben.wilson@digicert.com</a>]
<br>
<b>Sent:</b> Friday, October 24, 2014 12:47 PM<br>
<b>To:</b> Bruce Morton; Rick Andrews; Jeremy Rowley; CABFPub<br>
<b>Subject:</b> RE: Private key control<o:p></o:p></p>
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<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">Bruce,<o:p></o:p></p>
<p class="MsoNormal">I assume you’re not opposed to coming up with wording that is less specific but would at least eventually fill in content for section 3.2.1 of an RFC-3647-formatted CP, which is what I’d like us to be working toward. If we really want
to strip this down, even though I think we should address the MITM concern, then maybe we could just say something like, “Prior to issuing a Certificate, the CA MUST verify that the Applicant possesses the Private Key associated with the Public Key to be included
in the Certificate. The CA MAY verify this association by obtaining a CSR from the Applicant.” ?<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">In other words, I don’t think anyone wants to disrupt internal practices of CAs that comply with this textbook CA baseline practice, unless you are saying that for the Web PKI, proof of possession isn’t necessary. If you are, then do you
have an alternative you could propose? That’s what I’m looking for—something that we can all agree on that will fill a hole.<o:p></o:p></p>
<p class="MsoNormal">Thanks,<o:p></o:p></p>
<p class="MsoNormal">Ben <o:p></o:p></p>
<p class="MsoNormal"><span style="color:#1F497D"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="color:#1F497D"><o:p> </o:p></span></p>
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<p class="MsoNormal"><b><span style="font-size:10.0pt;font-family:"Tahoma","sans-serif"">From:</span></b><span style="font-size:10.0pt;font-family:"Tahoma","sans-serif"">
<a href="mailto:public-bounces@cabforum.org">public-bounces@cabforum.org</a> [<a href="mailto:public-bounces@cabforum.org">mailto:public-bounces@cabforum.org</a>]
<b>On Behalf Of </b>Bruce Morton<br>
<b>Sent:</b> Friday, October 24, 2014 8:19 AM<br>
<b>To:</b> Rick Andrews; Jeremy Rowley; CABFPub<br>
<b>Subject:</b> Re: [cabfpub] Private key control<o:p></o:p></span></p>
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<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal"><span style="color:#1F497D">I think the requirement should be dropped.<o:p></o:p></span></p>
<p class="MsoNormal"><span style="color:#1F497D"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="color:#1F497D">If we only validate the signature on the CSR, then we do not know if there is a man-in-the-middle. You need some other data.<o:p></o:p></span></p>
<p class="MsoNormal"><span style="color:#1F497D"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="color:#1F497D">If we want to technically validate private key control, then we should take some action such as sending the Subscriber some information out-of-band for signature. The signature would be compared to the signature
on the CSR to see if the same key was used.<o:p></o:p></span></p>
<p class="MsoNormal"><span style="color:#1F497D"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="color:#1F497D">The softer way that an OV/EV private key control is confirmed is by contacting the Subscriber out of band to confirm that they made/authenticate the request. I don’t think this works for DV. It will also not
work when the Subscriber can approve a certificate issuance with dual-factor login.<o:p></o:p></span></p>
<p class="MsoNormal"><span style="color:#1F497D"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="color:#1F497D">I don’t think we should have the requirement unless we suggest methods that will actually work for all certificate types and our current certificate management methods.<o:p></o:p></span></p>
<p class="MsoNormal"><span style="color:#1F497D"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="color:#1F497D">This requirement is not in the BRs or the EV guidelines and we have not been suffering from an incidents, so again, I think the requirement should be dropped.<o:p></o:p></span></p>
<p class="MsoNormal"><span style="color:#1F497D"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="color:#1F497D">Bruce.<o:p></o:p></span></p>
<p class="MsoNormal"><span style="color:#1F497D"><o:p> </o:p></span></p>
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<p class="MsoNormal"><b>From:</b> <a href="mailto:public-bounces@cabforum.org">public-bounces@cabforum.org</a> [<a href="mailto:public-bounces@cabforum.org">mailto:public-bounces@cabforum.org</a>]
<b>On Behalf Of </b>Rick Andrews<br>
<b>Sent:</b> Thursday, October 23, 2014 2:46 PM<br>
<b>To:</b> Jeremy Rowley; CABFPub<br>
<b>Subject:</b> Re: [cabfpub] Private key control<o:p></o:p></p>
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<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal"><span style="color:#1F497D">Jeremy,<o:p></o:p></span></p>
<p class="MsoNormal"><span style="color:#1F497D"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="color:#1F497D">How about “The CA MAY verify this association by obtaining a CSR from the Applicant and validating the signature on the CSR.”<o:p></o:p></span></p>
<p class="MsoNormal"><span style="color:#1F497D"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="color:#1F497D">-Rick<o:p></o:p></span></p>
<p class="MsoNormal"><span style="color:#1F497D"><o:p> </o:p></span></p>
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<p class="MsoNormal" style="margin-left:.5in"><b><span style="font-size:10.0pt;font-family:"Tahoma","sans-serif"">From:</span></b><span style="font-size:10.0pt;font-family:"Tahoma","sans-serif"">
<a href="mailto:public-bounces@cabforum.org">public-bounces@cabforum.org</a> [<a href="mailto:public-bounces@cabforum.org">mailto:public-bounces@cabforum.org</a>]
<b>On Behalf Of </b>Jeremy Rowley<br>
<b>Sent:</b> Wednesday, October 22, 2014 6:57 PM<br>
<b>To:</b> CABFPub<br>
<b>Subject:</b> [cabfpub] Private key control<o:p></o:p></span></p>
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<p class="MsoNormal" style="margin-left:.5in"><o:p> </o:p></p>
<p class="MsoNormal" style="mso-margin-top-alt:0in;margin-right:0in;margin-bottom:12.0pt;margin-left:.5in">
During the Code Signing BR discussion a few weeks ago, we noticed that the Baseline Requirements lack a definitive requirement for the CA to confirm that the Application is properly associated with the Public Key being included in the certificate. We’d like
to remedy this oversight. What does everyone thing about adding a section similar to the following to the BRs?<o:p></o:p></p>
<p class="MsoNormal" style="margin-left:.5in">Section 11.1.5 Verification of Key Pair Association<o:p></o:p></p>
<p class="MsoNormal" style="margin-left:.5in">Prior to issuing a Certificate, the CA MUST verify that the Applicant’s Private Key is properly associated with the Public Key and a subject name to be included in the Certificate. The CA MAY verify this association
by obtaining a CSR from the Applicant. <o:p></o:p></p>
<p class="MsoNormal" style="margin-left:.5in"><o:p> </o:p></p>
<p class="MsoNormal" style="margin-left:.5in">Jeremy<o:p></o:p></p>
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