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From: Christian Decker <decker.christian@gmail.com>
Date: Fri, 25 May 2012 09:47:23 +0200
Message-ID: <CALxbBHWe7KhTpdBYKmQ4XUuCdRLefNcdevG+GH7b9_+Sf2VCTw@mail.gmail.com>
To: Jeff Garzik <jgarzik@exmulti.com>
Content-Type: multipart/alternative; boundary=00151747be5894162f04c0d79675
Cc: bitcoin-development@lists.sourceforge.net
Subject: Re: [Bitcoin-development] Punishing empty blocks?
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How about a simple proof of work test? This one though does not ask for CPU
work but asks the miner for a random old transaction. If the miner really
stores the entire blockchain he will not have any problem answering to that
getdata request, whereas a botnet would have to ask someone else for it,
which could be detected if the response time deviates too much from what
has been previously measured (compare it against getdata for the block they
advertise). It's not perfect but it allows an estimate of whether it is a
chainless miner.

Regards,
Chris
--
Christian Decker



On Fri, May 25, 2012 at 3:17 AM, Jeff Garzik <jgarzik@exmulti.com> wrote:

> On Thu, May 24, 2012 at 8:57 PM, Luke-Jr <luke@dashjr.org> wrote:
> > Block times are not accurate enough for that.
>
> The times in your log are very accurate, assuming your system clock is
> remotely accurate.
>
> --
> Jeff Garzik
> exMULTI, Inc.
> jgarzik@exmulti.com
>
>
> ------------------------------------------------------------------------------
> Live Security Virtual Conference
> Exclusive live event will cover all the ways today's security and
> threat landscape has changed and how IT managers can respond. Discussions
> will include endpoint security, mobile security and the latest in malware
> threats. http://www.accelacomm.com/jaw/sfrnl04242012/114/50122263/
> _______________________________________________
> Bitcoin-development mailing list
> Bitcoin-development@lists.sourceforge.net
> https://lists.sourceforge.net/lists/listinfo/bitcoin-development
>

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How about a simple proof of work test? This one though does not ask for CPU=
 work but asks the miner for a random old transaction. If the miner really =
stores the entire blockchain he will not have any problem answering to that=
 getdata request, whereas a botnet would have to ask someone else for it, w=
hich could be detected if the response time deviates too much from what has=
 been previously measured (compare it against getdata for the block they ad=
vertise). It&#39;s not perfect but it allows an estimate of whether it is a=
 chainless miner.<div>

<br></div><div>Regards,</div><div>Chris</div><div>--<br>Christian Decker<br=
><br>
<br><br><div class=3D"gmail_quote">On Fri, May 25, 2012 at 3:17 AM, Jeff Ga=
rzik <span dir=3D"ltr">&lt;<a href=3D"mailto:jgarzik@exmulti.com" target=3D=
"_blank">jgarzik@exmulti.com</a>&gt;</span> wrote:<br><blockquote class=3D"=
gmail_quote" style=3D"margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-=
left:1ex">

<div class=3D"im">On Thu, May 24, 2012 at 8:57 PM, Luke-Jr &lt;<a href=3D"m=
ailto:luke@dashjr.org">luke@dashjr.org</a>&gt; wrote:<br>
&gt; Block times are not accurate enough for that.<br>
<br>
</div>The times in your log are very accurate, assuming your system clock i=
s<br>
remotely accurate.<br>
<div class=3D"im HOEnZb"><br>
--<br>
Jeff Garzik<br>
exMULTI, Inc.<br>
<a href=3D"mailto:jgarzik@exmulti.com">jgarzik@exmulti.com</a><br>
<br>
</div><div class=3D"HOEnZb"><div class=3D"h5">-----------------------------=
-------------------------------------------------<br>
Live Security Virtual Conference<br>
Exclusive live event will cover all the ways today&#39;s security and<br>
threat landscape has changed and how IT managers can respond. Discussions<b=
r>
will include endpoint security, mobile security and the latest in malware<b=
r>
threats. <a href=3D"http://www.accelacomm.com/jaw/sfrnl04242012/114/5012226=
3/" target=3D"_blank">http://www.accelacomm.com/jaw/sfrnl04242012/114/50122=
263/</a><br>
_______________________________________________<br>
Bitcoin-development mailing list<br>
<a href=3D"mailto:Bitcoin-development@lists.sourceforge.net">Bitcoin-develo=
pment@lists.sourceforge.net</a><br>
<a href=3D"https://lists.sourceforge.net/lists/listinfo/bitcoin-development=
" target=3D"_blank">https://lists.sourceforge.net/lists/listinfo/bitcoin-de=
velopment</a><br>
</div></div></blockquote></div><br></div>

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