<div dir="ltr"><div class="gmail_default" style="font-family:arial,helvetica,sans-serif"><span style="font-family:arial,sans-serif">On Fri, Dec 30, 2016 at 4:22 PM, Adrian Tymes </span><span dir="ltr" style="font-family:arial,sans-serif"><<a href="mailto:atymes@gmail.com" target="_blank">atymes@gmail.com</a>></span><span style="font-family:arial,sans-serif"> wrote:</span><br></div><div class="gmail_extra"><div class="gmail_quote"><font color="#500050"><br></font><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left-width:1px;border-left-color:rgb(204,204,204);border-left-style:solid;padding-left:1ex">
<div class="gmail_default" style="font-family:arial,helvetica,sans-serif;display:inline">​> ​</div>In your example, you could do the same for your videos, proving that<br>
*you say that* you have an older video.  This does not absolutely<br>
prove that you actually had that earlier video, just that you say that<br>
you do.<div class="gmail_default" style="font-family:arial,helvetica,sans-serif;display:inline">​ ​</div>In neither case does NIST actually sign anything. </blockquote><div><br></div><div><div class="gmail_default" style="font-family:arial,helvetica,sans-serif;display:inline">​<font size="4">But why couldn't NIST sign it? ​</font></div><font size="4"> <div class="gmail_default" style="font-family:arial,helvetica,sans-serif;display:inline">​I send my video to NIST and a few seconds later they send me a file signed with NIST's private key that says "we received your video ​and made this hash of it at time X". Then if somebody produces a different version of the video with a time stamp later than X on it I can produce the signed hash of the earlier video proving the later one must be </div><span style="font-family:arial,helvetica,sans-serif">phony<div class="gmail_default" style="font-family:arial,helvetica,sans-serif;display:inline">​;​</div> provided <div class="gmail_default" style="font-family:arial,helvetica,sans-serif;display:inline">​of course ​</div>it<div class="gmail_default" style="font-family:arial,helvetica,sans-serif;display:inline">​ is</div> generally agreed that NIST is honest.<div class="gmail_default" style="font-family:arial,helvetica,sans-serif;display:inline">​ </div></span></font></div><div><span style="font-family:arial,helvetica,sans-serif"><div class="gmail_default" style="font-family:arial,helvetica,sans-serif;display:inline"><font size="4"> John K Clark</font></div></span></div><div><span style="font-family:arial,helvetica,sans-serif"><br></span></div><div><br></div><div class="HOEnZb"><div class="h5"><br>
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