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<div class="moz-cite-prefix">On 4/2/2019 11:53 AM, Salz, Rich wrote:<br>
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<ul style="margin-top:0in" type="disc">
<li class="MsoListParagraph"
style="margin-left:0in;mso-list:l0 level1 lfo1">It is a
<b><u>monumentally bad idea</u></b> to retain revoked key
material<o:p></o:p></li>
</ul>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">+1, +2, +1000!<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">If you want a chain of trust, when you
generate key “N+1” sign it with key “N”. Repeat for each
generation.</p>
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<p><br>
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<p>The problem with this is that you need to know *when* N signed
N+1, and you can't believe N about the time. (E.g. in 2020, I use
key 2010 to sign key 2017 well after 2010 was revoked, at the same
time I sign Fake2017, and lead a chain of trust through Fake2017
for future signings). This problem is at the root of why a
simple chain of trust won't work. I'm trying to figure out a way
to mix-in something to tie each transaction to a point in time (or
at least an order in time) in a manner that possession of a key
(revoked or not) earlier in the chain doesn't allow you to lie
about what comes after. I don't know that its possible to do
that automatically. It may require a human making a trust
decision based on other non-DNS information.</p>
<p>[5011 works because each resolver updates its state as things
happen, so twiddling with the signing chain a year or two after a
key is revoked won't cause the resolver to update its state as the
key is either not in trust anchor set, or is there in a revoked
state. Trying to replicate this behavior with a resolver that's
been offline for two years just won't work].<br>
</p>
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<blockquote type="cite"
cite="mid:1DFCE595-B3DF-4150-ADEB-538B02CD57E9@akamai.com">
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<p class="MsoNormal"><o:p></o:p></p>
<div>
<p class="MsoNormal"><o:p> </o:p></p>
<ul style="margin-top:0in" type="disc">
<li class="MsoListParagraph"
style="margin-left:0in;mso-list:l0 level1 lfo1">This is
not a case where holding on to the past preserves the
future.<o:p></o:p></li>
</ul>
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<div>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">Nice turn of phrase!<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
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<p>Thanks!</p>
<p>Mike</p>
<p><br>
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<p><br>
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