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<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D">8 bytes of entropy in the serialNumber field has been a requirement of Microsoft’s root program since 2013: http://social.technet.microsoft.com/wiki/contents/articles/1760.windows-root-certificate-program-technical-requirements-version-2-0/revision/15.aspx<o:p></o:p></span></p>
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<p class="MsoNormal"><b><span style="font-size:11.0pt;font-family:"Calibri",sans-serif">From:</span></b><span style="font-size:11.0pt;font-family:"Calibri",sans-serif"> public-bounces@cabforum.org [mailto:public-bounces@cabforum.org]
<b>On Behalf Of </b>Ryan Sleevi<br>
<b>Sent:</b> Wednesday, October 28, 2015 2:16 PM<br>
<b>To:</b> Doug Beattie <doug.beattie@globalsign.com><br>
<b>Cc:</b> Nazmus Sakib <mdsakib@microsoft.com>; Magnus Nyström <mnystrom@microsoft.com>; public@cabforum.org<br>
<b>Subject:</b> Re: [cabfpub] Microsoft Proposed Updates to the SHA-1 Deprecation Timeline<o:p></o:p></span></p>
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<p class="MsoNormal">On Wed, Oct 28, 2015 at 2:03 PM, Doug Beattie <<a href="mailto:doug.beattie@globalsign.com" target="_blank">doug.beattie@globalsign.com</a>> wrote:<o:p></o:p></p>
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<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"><span style="color:#1F497D">With the certificate serial number entropy</span><o:p></o:p></p>
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<p class="MsoNormal">This is not a MUST requirement in the Baseline Requirements, unfortunately.<o:p></o:p></p>
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<p class="MsoNormal">Section 7.1<o:p></o:p></p>
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<p class="MsoNormal">"CAs SHOULD generate non-sequential Certificate serial numbers that exhibit at least 20 bits of entropy"<o:p></o:p></p>
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<p class="MsoNormal">As such, it's not a terribly reliable scheme.<o:p></o:p></p>
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