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<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D">This is why I proposed and continue to support an actual definition. If people don’t like my definition, I’m open to improvements. I don’t think it should
be too hard to come up with one that excludes the four examples Doug mentioned, and I think mine currently does.<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D">-Tim<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";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";color:windowtext">From:</span></b><span style="font-size:10.0pt;font-family:"Tahoma","sans-serif";color:windowtext"> public-bounces@cabforum.org [mailto:public-bounces@cabforum.org]
<b>On Behalf Of </b>Doug Beattie<br>
<b>Sent:</b> Friday, April 22, 2016 11:50 AM<br>
<b>To:</b> Bruce Morton; Ben Wilson; Dimitris Zacharopoulos; public@cabforum.org<br>
<b>Subject:</b> Re: [cabfpub] Pre-Ballot 164 - Certificate Serial Number Entropy<o:p></o:p></span></p>
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<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D">Is there a clear definition of what we mean by Entropy and/or unpredictable bits? Are any/all of these acceptable:<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D">- Hash of the current date/time<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D">- Hash of the date/time in the certificate<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D">- Using the MS GUID generator<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D">- A lousy random number generator<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D">While we can all look in CT logs for sufficiently long serial numbers, it’s not possible to tell if they were generated with the entropy needed to comply, thus
the request. I think Ryan asked this question earlier this week. <o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D">Is this requirement to use sufficient long serial numbers, or to use sufficiently long serial numbers with a minimum level of entropy, randomness or unpredictability?
If it’s the latter, then don’t we need to define what we mean? I don’t see the point in asking for longer serial numbers if there is no spec around the quality of the randomness in the serial number – maybe there is one, but it’s not obvious from the discussion.<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D">Doug<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D"><o:p> </o:p></span></p>
<p class="MsoNormal"><a name="_MailEndCompose"></a><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D"><o:p> </o:p></span></p>
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<p class="MsoNormal" style="margin-left:.5in"><b><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:windowtext">From:</span></b><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:windowtext">
<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, April 22, 2016 11:15 AM<br>
<b>To:</b> Ben Wilson <<a href="mailto:ben.wilson@digicert.com">ben.wilson@digicert.com</a>>; Dimitris Zacharopoulos <<a href="mailto:jimmy@it.auth.gr">jimmy@it.auth.gr</a>>;
<a href="mailto:public@cabforum.org">public@cabforum.org</a><br>
<b>Subject:</b> Re: [cabfpub] Pre-Ballot 164 - Certificate Serial Number Entropy<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="margin-left:.5in"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D">I would think that July 1, 2016 would be a good starting point. Would be good to get feedback from any CAs whose product does not support
this.<o:p></o:p></span></p>
<p class="MsoNormal" style="margin-left:.5in"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D"><o:p> </o:p></span></p>
<p class="MsoNormal" style="margin-left:.5in"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D">Bruce.<o:p></o:p></span></p>
<p class="MsoNormal" style="margin-left:.5in"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D"><o:p> </o:p></span></p>
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<p class="MsoNormal" style="margin-left:.5in"><b><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:windowtext">From:</span></b><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:windowtext">
<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>Ben Wilson<br>
<b>Sent:</b> Friday, April 22, 2016 10:43 AM<br>
<b>To:</b> Dimitris Zacharopoulos <<a href="mailto:jimmy@it.auth.gr">jimmy@it.auth.gr</a>>;
<a href="mailto:public@cabforum.org">public@cabforum.org</a><br>
<b>Subject:</b> Re: [cabfpub] Pre-Ballot 164 - Certificate Serial Number Entropy<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="margin-left:.5in"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:windowtext">I’d like suggestions on an effective date.<o:p></o:p></span></p>
<p class="MsoNormal" style="margin-left:.5in"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:windowtext"><o:p> </o:p></span></p>
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<p class="MsoNormal" style="margin-left:.5in"><b><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:windowtext">From:</span></b><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:windowtext">
<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>Dimitris Zacharopoulos<br>
<b>Sent:</b> Friday, April 22, 2016 2:23 AM<br>
<b>To:</b> <a href="mailto:public@cabforum.org">public@cabforum.org</a><br>
<b>Subject:</b> Re: [cabfpub] Pre-Ballot 164 - Certificate Serial Number Entropy<o:p></o:p></span></p>
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<p class="MsoNormal" style="margin-left:.5in"><o:p> </o:p></p>
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<p class="MsoNormal" style="margin-left:.5in">On 21/4/2016 4:07 πμ, Jacob Hoffman-Andrews wrote:<o:p></o:p></p>
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<p class="MsoNormal" style="margin-left:.5in">I think the question of how to define entropy or CSPRNGs is a really good one, but I think the core of this ballot, changing a SHOULD to a SHALL, is too important to hold up on that complex question. How about a
version which is strictly no more ambiguous that the current version: <o:p></o:p></p>
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<p style="margin-left:.5in"><span style="font-size:9.5pt">"Effective April 1, 2016, CAs SHALL use a Certificate serialNumber greater than zero (0) that exhibits at least 64 bits of entropy."<o:p></o:p></span></p>
<p style="margin-left:.5in"><span style="font-size:9.5pt">Let's Encrypt would be happy to endorse such a ballot.<o:p></o:p></span></p>
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<o:p> </o:p></p>
<pre style="margin-left:.5in">_______________________________________________<o:p></o:p></pre>
<pre style="margin-left:.5in">Public mailing list<o:p></o:p></pre>
<pre style="margin-left:.5in"><a href="mailto:Public@cabforum.org">Public@cabforum.org</a><o:p></o:p></pre>
<pre style="margin-left:.5in"><a href="http://scanmail.trustwave.com/?c=4062&d=xcia15LZj7OX3h3R_NA-lpiGLbDMK-NzBsHsUQPI3w&s=5&u=https%3a%2f%2fcabforum%2eorg%2fmailman%2flistinfo%2fpublic">https://cabforum.org/mailman/listinfo/public</a><o:p></o:p></pre>
</blockquote>
<p class="MsoNormal" style="margin-left:.5in"><br>
In order to make this rule a little clearer, we suggest changing it to:<br>
<br>
"Effective XXXX, 2016, CAs SHALL use a Certificate serialNumber greater than zero (0) that exhibits at least 64 bits of entropy for all issued certificates, including CA certificates".<br>
<br>
Since this discussion begun in February, I suppose the effective date will be adjusted accordingly to a date after the ballot and not "April 1, 2016".<br>
<br>
<br>
Dimitris.<o:p></o:p></p>
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