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From: Mike Brooks <m@ib.tc>
Date: Thu, 8 Oct 2020 17:16:40 -0700
Message-ID: <CALFqKjTOKAE=zh6EZEzK+Y1xdJiy_F33S43=dryJv9oKWG02NQ@mail.gmail.com>
To: Pieter Wuille <bitcoin-dev@wuille.net>
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Cc: Bitcoin Protocol Discussion <bitcoin-dev@lists.linuxfoundation.org>
Subject: Re: [bitcoin-dev] Progress on Miner Withholding - FPNC
Precedence: list

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Pieter,

You are correct.

And also, I did prove what I set out to prove. The code provided privately
to the security team will in fact consume 99% of the CPU, which means it
does have an effect on the electorate.  It is true the node still
stubbornly passes messages, but I would argue that this is still very much
a problem that would concern operators, and perhaps the threshold for a
patch is much too high.  A layered security system like what is found in
bitcoin necessitates an attack chain.  The `getdata` message is an implicit
information disclosure that allows for the identification of dissenting
nodes.   As ZmnSCPxj pointed out, block mixing will give preemption at most
67% of the network, and the remaining dissenting nodes can be quelled by
maxing out their processing power.  All of this can be used together to
make sure that a withheld block becomes the prevailing solution.

FPNC rebalances incentives to serve the interests of the network, and
fundamentally resolves a class of abuses that reshape the electorate.  FPNC
will produce a more deceliterized and fair network than "first seen."

Cheers,
Mike

On Wed, Oct 7, 2020 at 5:12 PM Pieter Wuille <bitcoin-dev@wuille.net> wrote=
:

> On Wednesday, October 7, 2020 1:31 PM, Mike Brooks via bitcoin-dev <
> bitcoin-dev@lists.linuxfoundation.org> wrote:
>
> But first of all, I'd like to say that the idea for FPNC came out of a
> conversation with ZmnSCPxj's in regards to re-org stability.  When I had
> proposed blockchain pointers with the PubRef opcode, he took the time to
> explain to me concerns around re-orgs and why it is a bigger problem than=
 I
> initially had thought =E2=80=94 and I greatly appreciate this detail.   A=
fter
> touching base with ZmnSCPxj and Greg Maxwell there is an overwhelming vie=
w
> that the current problems that face the network outweigh any theoretical
> ones.
>
>
> Greg Maxwell isn't on this list, but assuming this is about the conversio=
n
> you've had on Bitcoin Core's security disclosure list, I believe this is =
a
> misrepresentation. The discussion has been mostly around a DoS attack
> report which turned out to be a mistake.
>
> Cheers,
>
> --
> Pieter
>
>
>

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<div dir=3D"ltr">Pieter,<div><br></div><div>You are correct.</div><div><br>=
</div><div>And also, I did prove what I set out to prove. The code provided=
 privately to the security team will in fact consume 99% of the CPU, which =
means it does have an effect on the electorate.=C2=A0 It is true the node s=
till stubbornly passes messages, but I would argue that this is still very =
much a=C2=A0problem that would concern operators, and perhaps the threshold=
 for a patch is much too high.=C2=A0 A layered security system like what is=
 found in bitcoin necessitates an attack chain.=C2=A0 The `getdata` message=
 is an implicit information disclosure that allows for the identification o=
f dissenting nodes.=C2=A0 =C2=A0As ZmnSCPxj pointed out, block mixing will =
give preemption=C2=A0at most 67% of the network, and the remaining=C2=A0dis=
senting nodes can be quelled=C2=A0by maxing out their processing power.=C2=
=A0 All of this can be used together to make sure that a withheld block bec=
omes the prevailing solution.</div><div><br></div><div>FPNC rebalances ince=
ntives to serve the interests of the network, and fundamentally resolves a =
class of abuses that reshape the electorate.=C2=A0 FPNC will produce a more=
 deceliterized and fair network than &quot;first seen.&quot;</div><div><br>=
</div><div>Cheers,</div><div>Mike</div></div><br><div class=3D"gmail_quote"=
><div dir=3D"ltr" class=3D"gmail_attr">On Wed, Oct 7, 2020 at 5:12 PM Piete=
r Wuille &lt;<a href=3D"mailto:bitcoin-dev@wuille.net">bitcoin-dev@wuille.n=
et</a>&gt; wrote:<br></div><blockquote class=3D"gmail_quote" style=3D"margi=
n:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex=
"><div>On Wednesday, October 7, 2020 1:31 PM, Mike Brooks via bitcoin-dev &=
lt;<a href=3D"mailto:bitcoin-dev@lists.linuxfoundation.org" target=3D"_blan=
k">bitcoin-dev@lists.linuxfoundation.org</a>&gt; wrote:<br></div><div> <br>=
</div><blockquote type=3D"cite"><div dir=3D"ltr"><div dir=3D"auto"><div dir=
=3D"ltr"><div>But first of all, I&#39;d like to say that the idea for FPNC =
came out of a conversation=C2=A0with ZmnSCPxj&#39;s in regards to=C2=A0re-o=
rg stability.=C2=A0 When I had proposed blockchain pointers with the PubRef=
 opcode, he took the time to explain to me concerns around re-orgs and why =
it is a bigger problem than I initially had thought=C2=A0=E2=80=94 and I gr=
eatly appreciate this detail.=C2=A0 =C2=A0After touching base with ZmnSCPxj=
 and Greg Maxwell there is an overwhelming view that the current problems t=
hat face the network outweigh any theoretical ones.<br></div></div></div></=
div></blockquote><div><br></div><table><tbody><tr><td>Greg Maxwell isn&#39;=
t on this list, but assuming this is about the conversion you&#39;ve had on=
 Bitcoin Core&#39;s security disclosure list, I believe this is a misrepres=
entation. The discussion has been mostly around a DoS attack report which t=
urned out to be a mistake.<br><br>Cheers,<br><br>-- <br>Pieter<br><br></td>=
</tr></tbody></table><div><br></div></blockquote></div>

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