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</o:shapelayout></xml><![endif]--></head><body lang=EN-US link=blue vlink=purple><div class=WordSection1><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'><o:p> </o:p></span></p><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"'> extropy-chat-bounces@lists.extropy.org [mailto:extropy-chat-bounces@lists.extropy.org] <b>On Behalf Of </b>Kelly Anderson<br><b>Sent:</b> Friday, April 19, 2013 4:14 PM<br><b>To:</b> ExI chat list<br><b>Subject:</b> Re: [ExI] proto-bitcoin<o:p></o:p></span></p><p class=MsoNormal><o:p> </o:p></p><div><div><div><p class=MsoNormal>On Thu, Apr 18, 2013 at 11:32 AM, spike <<a href="mailto:spike@rainier66.com" target="_blank">spike@rainier66.com</a>> wrote:<o:p></o:p></p><div><div><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'><span style='color:#1F497D'>>>…</span>GIMPS is an organized search for the record prime number, but it occurred to me that it is kinda sorta like a prototype of bitcoin<span style='color:#1F497D'>…<o:p></o:p></span></p><p class=MsoNormal style='margin-bottom:12.0pt'><br><span style='color:#1F497D'>>…</span>The ability to have a huge amount of work required to find the excessively weird case, but a trivial amount of work to verify it is what makes Bitcoin work<span style='color:#1F497D'>…</span>-Kelly<o:p></o:p></p></div></div></div></div></div><p class=MsoNormal style='margin-bottom:12.0pt'><o:p> </o:p></p><p class=MsoNormal style='margin-bottom:12.0pt'><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'>Thanks Kelly, I think you verified what I was saying to start with: that GIMPS is analogous to bitcoin. It is close enough for approximation purposes to say that there are about 30,000 average modern desktop computers dedicated to GIMPS and we get a new Mersenne prime about every three years or so on the average, so it works well enough to say that finding a Mersenne prime today takes about 100k computer years. If you find one, it takes about a month to verify it, so it takes about a millionth time to verify as it took to find.<o:p></o:p></span></p><p class=MsoNormal style='margin-bottom:12.0pt'><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'>Bitcoin hipsters, does this sound about right? Your computer can verify a bitcoin genuine in about a millionth the computing time it took to mine the coin to start with? Or am I grossly misunderstanding Bitcoin?<o:p></o:p></span></p><p class=MsoNormal style='margin-bottom:12.0pt'><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'>spike<o:p></o:p></span></p><p class=MsoNormal style='margin-bottom:12.0pt'><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'><o:p> </o:p></span></p></div></body></html>