From: "Kenshiro []" <tensiam@hotmail.com>
To: Alistair Mann <al@pectw.net>, Bitcoin Protocol Discussion
	<bitcoin-dev@lists.linuxfoundation.org>
Thread-Topic: [bitcoin-dev] Add a moving checkpoint to the Bitcoin protocol
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Date: Wed, 31 Jul 2019 14:53:25 +0000
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Subject: Re: [bitcoin-dev] Add a moving checkpoint to the Bitcoin protocol
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P.S.: To be clearer, in this example I set an N value of 144 blocks, which =
is approximately 24 hours.

________________________________
From: Kenshiro [] <tensiam@hotmail.com>
Sent: Wednesday, July 31, 2019 16:40
To: Alistair Mann <al@pectw.net>; Bitcoin Protocol Discussion <bitcoin-dev@=
lists.linuxfoundation.org>
Subject: Re: [bitcoin-dev] Add a moving checkpoint to the Bitcoin protocol

>>> How would a (potentially, state-sponsored) netsplit lasting longer than=
 N be
handled?

It would be detected by the community much before reaching the reorg limit =
of N blocks (it's 24 hours) so nodes could stop until the netsplit is fixed=
.

In the extreme case no one notice the network split during more than N bloc=
ks (24 hours) and there are 2 permanent forks longer than N, nodes from one=
 branch could delete their local history so they would join the other branc=
h.

Regards,


________________________________
From: Alistair Mann <al@pectw.net>
Sent: Wednesday, July 31, 2019 15:59
To: Kenshiro [] <tensiam@hotmail.com>; Bitcoin Protocol Discussion <bitcoin=
-dev@lists.linuxfoundation.org>
Subject: Re: [bitcoin-dev] Add a moving checkpoint to the Bitcoin protocol

On Wednesday 31 Jul 2019 12:28:58 Kenshiro [] via bitcoin-dev wrote:

> I would like to propose that a "moving checkpoint" is added to the Bitcoi=
n
> protocol. It's a very simple rule already implemented in NXT coin:
>
> - A node will ignore any new block under nodeBlockHeight - N, so the
> blockchain becomes truly immutable after N blocks, even during a 51% atta=
ck
> which thanks to the moving checkpoint can't rewrite history older than th=
e
> last N blocks.

How would a (potentially, state-sponsored) netsplit lasting longer than N b=
e
handled?
--
Alistair Mann


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P.S.: To be clearer, in this example I set an N value of 144 blocks, which =
is approximately 24 hours.</div>
<div>
<div id=3D"appendonsend"></div>
<div style=3D"font-family:Calibri,Helvetica,sans-serif; font-size:12pt; col=
or:rgb(0,0,0)">
<br>
</div>
<hr tabindex=3D"-1" style=3D"display:inline-block; width:98%">
<div id=3D"divRplyFwdMsg" dir=3D"ltr"><font face=3D"Calibri, sans-serif" co=
lor=3D"#000000" style=3D"font-size:11pt"><b>From:</b> Kenshiro [] &lt;tensi=
am@hotmail.com&gt;<br>
<b>Sent:</b> Wednesday, July 31, 2019 16:40<br>
<b>To:</b> Alistair Mann &lt;al@pectw.net&gt;; Bitcoin Protocol Discussion =
&lt;bitcoin-dev@lists.linuxfoundation.org&gt;<br>
<b>Subject:</b> Re: [bitcoin-dev] Add a moving checkpoint to the Bitcoin pr=
otocol</font>
<div>&nbsp;</div>
</div>
<div dir=3D"ltr">
<div style=3D"font-family:Calibri,Helvetica,sans-serif; font-size:12pt; col=
or:rgb(0,0,0)">
&gt;&gt;&gt;&nbsp;<span>How would a (potentially, state-sponsored) netsplit=
 lasting longer than N be
<br>
</span><span>handled? &nbsp;</span></div>
<div style=3D"font-family:Calibri,Helvetica,sans-serif; font-size:12pt; col=
or:rgb(0,0,0)">
<span><br>
</span></div>
<div style=3D"font-family:Calibri,Helvetica,sans-serif; font-size:12pt; col=
or:rgb(0,0,0)">
<span>It would be detected by the community much before reaching the reorg =
limit of N blocks (it's 24 hours) so nodes could stop until the netsplit is=
 fixed.&nbsp;</span></div>
<div style=3D"font-family:Calibri,Helvetica,sans-serif; font-size:12pt; col=
or:rgb(0,0,0)">
<span><br>
</span></div>
<div style=3D"font-family:Calibri,Helvetica,sans-serif; font-size:12pt; col=
or:rgb(0,0,0)">
<span>In the extreme case no one notice the network split during more than =
N blocks (24 hours) and there are 2 permanent forks longer than N, n</span>=
odes from one branch could delete their local history so they would join th=
e other branch.</div>
<div style=3D"font-family:Calibri,Helvetica,sans-serif; font-size:12pt; col=
or:rgb(0,0,0)">
<br>
</div>
<div style=3D"font-family:Calibri,Helvetica,sans-serif; font-size:12pt; col=
or:rgb(0,0,0)">
Regards,</div>
<div style=3D"font-family:Calibri,Helvetica,sans-serif; font-size:12pt; col=
or:rgb(0,0,0)">
<br>
</div>
<div>
<div id=3D"x_appendonsend"></div>
<div style=3D"font-family:Calibri,Helvetica,sans-serif; font-size:12pt; col=
or:rgb(0,0,0)">
<br>
</div>
<hr tabindex=3D"-1" style=3D"display:inline-block; width:98%">
<div id=3D"x_divRplyFwdMsg" dir=3D"ltr"><font face=3D"Calibri, sans-serif" =
color=3D"#000000" style=3D"font-size:11pt"><b>From:</b> Alistair Mann &lt;a=
l@pectw.net&gt;<br>
<b>Sent:</b> Wednesday, July 31, 2019 15:59<br>
<b>To:</b> Kenshiro [] &lt;tensiam@hotmail.com&gt;; Bitcoin Protocol Discus=
sion &lt;bitcoin-dev@lists.linuxfoundation.org&gt;<br>
<b>Subject:</b> Re: [bitcoin-dev] Add a moving checkpoint to the Bitcoin pr=
otocol</font>
<div>&nbsp;</div>
</div>
<div class=3D"x_BodyFragment"><font size=3D"2"><span style=3D"font-size:11p=
t">
<div class=3D"x_PlainText">On Wednesday 31 Jul 2019 12:28:58 Kenshiro [] vi=
a bitcoin-dev wrote:<br>
<br>
&gt; I would like to propose that a &quot;moving checkpoint&quot; is added =
to the Bitcoin<br>
&gt; protocol. It's a very simple rule already implemented in NXT coin:<br>
&gt; <br>
&gt; - A node will ignore any new block under nodeBlockHeight - N, so the<b=
r>
&gt; blockchain becomes truly immutable after N blocks, even during a 51% a=
ttack<br>
&gt; which thanks to the moving checkpoint can't rewrite history older than=
 the<br>
&gt; last N blocks.<br>
<br>
How would a (potentially, state-sponsored) netsplit lasting longer than N b=
e <br>
handled?&nbsp; <br>
-- <br>
Alistair Mann<br>
<br>
</div>
</span></font></div>
</div>
</div>
</div>
</body>
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