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Date: Mon, 23 Dec 2013 17:51:41 -0800
Message-ID: <CAO7N=i1avBNy9wfQSAyDH19ywJ__C_A9XSVBbufa42=Lu4MjRg@mail.gmail.com>
From: Ryan Carboni <ryan.jc.pc@gmail.com>
To: Mark Friedenbach <mark@monetize.io>,
	bitcoin-development@lists.sourceforge.net
Content-Type: multipart/alternative; boundary=e89a8f234b555fbcf304ee3dfcd1
Subject: Re: [Bitcoin-development] Bitcoin difficulty sanity check suggestion
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I think you misunderstood my statement. If time > 3 days, and after 4
blocks have been mined, then difficulty would be reset.

In theory, one would have to isolate roughly one percent of the Bitcoin
network's hashing power to do so. Which would indicate an attack by a state
actor as opposed to anything else. Arguably, the safest way to run Bitcoin
is through a proprietary dial-up network.


On Sun, Dec 22, 2013 at 7:22 PM, Mark Friedenbach <mark@monetize.io> wrote:

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> Hash: SHA1
>
> Ryan, these sort of adjustments introduce security risks. If you were
> isolated from the main chain by a low-hashpower attacker, how would
> you know? They'd need just three days without you noticing that
> network block generation has stalled - maybe they wait for a long
> weekend - then after that the block rate is normal but completely
> controlled by the attacker (and isolated from mainnet).
>
> There are fast acting alternative difficulty adjustment algorithms
> being explored by some alts, such as the 9-block interval, 144-block
> window, Parks-McClellan FIR filter used by Freicoin to recover from
> just such a mining bubble. If it were to happen to bitcoin, there
> would be sophisticated alternative to turn to, and enough time to make
> the change.
>
> On 12/22/2013 07:10 PM, Ryan Carboni wrote:
> > I think Bitcoin should have a sanity check: after three days if
> > only four blocks have been mined, difficulty should be adjusted
> > downwards.
> >
> > This might become important in the near future. I project a
> > Bitcoin mining bubble.
> >
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<div dir=3D"ltr">I think you misunderstood my statement. If time &gt; 3 day=
s, and after 4 blocks have been mined, then difficulty would be reset.<div>=
<br></div><div>In theory, one would have to isolate roughly one percent of =
the Bitcoin network&#39;s hashing power to do so. Which would indicate an a=
ttack by a state actor as opposed to anything else. Arguably, the safest wa=
y to run Bitcoin is through a proprietary dial-up network.</div>
</div><div class=3D"gmail_extra"><br><br><div class=3D"gmail_quote">On Sun,=
 Dec 22, 2013 at 7:22 PM, Mark Friedenbach <span dir=3D"ltr">&lt;<a href=3D=
"mailto:mark@monetize.io" target=3D"_blank">mark@monetize.io</a>&gt;</span>=
 wrote:<br>
<blockquote class=3D"gmail_quote" style=3D"margin:0 0 0 .8ex;border-left:1p=
x #ccc solid;padding-left:1ex">-----BEGIN PGP SIGNED MESSAGE-----<br>
Hash: SHA1<br>
<br>
Ryan, these sort of adjustments introduce security risks. If you were<br>
isolated from the main chain by a low-hashpower attacker, how would<br>
you know? They&#39;d need just three days without you noticing that<br>
network block generation has stalled - maybe they wait for a long<br>
weekend - then after that the block rate is normal but completely<br>
controlled by the attacker (and isolated from mainnet).<br>
<br>
There are fast acting alternative difficulty adjustment algorithms<br>
being explored by some alts, such as the 9-block interval, 144-block<br>
window, Parks-McClellan FIR filter used by Freicoin to recover from<br>
just such a mining bubble. If it were to happen to bitcoin, there<br>
would be sophisticated alternative to turn to, and enough time to make<br>
the change.<br>
<div><div class=3D"h5"><br>
On 12/22/2013 07:10 PM, Ryan Carboni wrote:<br>
&gt; I think Bitcoin should have a sanity check: after three days if<br>
&gt; only four blocks have been mined, difficulty should be adjusted<br>
&gt; downwards.<br>
&gt;<br>
&gt; This might become important in the near future. I project a<br>
&gt; Bitcoin mining bubble.<br>
&gt;<br>
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" target=3D"_blank">http://www.enigmail.net/</a><br>
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</blockquote></div><br></div>

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