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Cc: Bitcoin Dev <bitcoin-development@lists.sourceforge.net>,
	Ryan Carboni <ryan.jc.pc@gmail.com>
Subject: Re: [Bitcoin-development] Bitcoin difficulty sanity check suggestion
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Mark, thank you for a very clear explanation of why this proposal would be
dangerous.

What I have noted in many discussions regarding blockchain security and
proof-or-work schemes, is there is a wide gulf between those few people who
can clearly reason about it, and those who have a lot trouble with it (I
mostly fall into the later camp).

I wonder if anyone can point to resources who can help "the rest of us"
reason clearly about these types of proposals, prior to bringing them to
this list or a senior dev.

Ideally it would illustrate various past proposals, explain why they would
and wouldnt work, and build up some fundamental concepts, like a "Newtons
laws of blockchain security" that would help us evaluate such ideas on our
own.

Blockchain stuff is often counterintuitive.



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

> -----BEGIN PGP SIGNED MESSAGE-----
> 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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>
> ------------------------------------------------------------------------------
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>



-- 
Robin R Chauhan
CEO, Pathway Intelligence Inc
robin@pathwayi.com
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Cell: 604-865-0517
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<div dir=3D"ltr">Mark, thank you for a very clear explanation of why this p=
roposal would be dangerous.<br><br>What I have noted in many discussions re=
garding blockchain security and proof-or-work schemes, is there is a wide g=
ulf between those few people who can clearly reason about it, and those who=
 have a lot trouble with it (I mostly fall into the later camp).<div>
<br></div><div>I wonder if anyone can point to resources who can help &quot=
;the rest of us&quot; reason clearly about these types of proposals, prior =
to bringing them to this list or a senior dev. =A0<br><br>Ideally it would =
illustrate various past proposals, explain why they would and wouldnt work,=
 and build up some fundamental concepts, like a &quot;Newtons laws of block=
chain security&quot; that would help us evaluate such ideas on our own.</di=
v>
<div><br></div><div>Blockchain stuff is often counterintuitive.</div><div><=
br></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>&g=
t;</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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Comment: Using GnuPG with Thunderbird - <a href=3D"http://www.enigmail.net/=
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<br>
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Rapidly troubleshoot problems before they affect your business. Most IT<br>
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<br>
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velopment</a><br>
</blockquote></div><br><br clear=3D"all"><div><br></div>-- <br><div dir=3D"=
ltr"><div>Robin R Chauhan</div><div>CEO, Pathway Intelligence Inc</div><div=
><a href=3D"mailto:robin@pathwayi.com" target=3D"_blank">robin@pathwayi.com=
</a></div>
<div>Office: 778-588-6217 Ext. 201</div><div>Cell: 604-865-0517</div><div>F=
ax: 778-588-1042</div><div><a href=3D"http://pathwayi.com/" target=3D"_blan=
k">http://pathwayi.com/</a></div><div>-------------------------------------=
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