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From: Erik Aronesty <erik@q32.com>
Date: Mon, 11 Jul 2022 16:52:39 -0400
Message-ID: <CAJowKg+cm5WeC0L=rfexd2n5fstSXw2sqMo1ZGR3unuqBJ8swA@mail.gmail.com>
To: "Russell O'Connor" <roconnor@blockstream.com>, 
 Bitcoin Protocol Discussion <bitcoin-dev@lists.linuxfoundation.org>
Content-Type: multipart/alternative; boundary="0000000000003107e305e38dbcf5"
Subject: Re: [bitcoin-dev] Security problems with relying on transaction
 fees for security
Precedence: list

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>
> Miners will learn to create anyone-can-spend outputs to bribe other miners
> to build on their block rather than reorg it.  (Due to the coinbase
> maturity, this will require some amount of floating capital.)
>

(reward + avg fee) * 144 * 365 (one year) == approximate investment needed
to reorg the chain for a double-spend attack

in 30 years, assuming fees are still negligible (why wouldn't they be?
layer 2 works and layer 3 is coming), that's only 1200 bitcoin.  not really
a lot.

there's only few things that allow that security budget to be ok

 - we assume the price goes up a lot
 - we assume transactions get a lot more expensive
 - we don't care about double-spend attacks for very large transactions

i'd rather engineer block demand than ignore it

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<div dir=3D"ltr"><div class=3D"gmail_quote"><blockquote class=3D"gmail_quot=
e" style=3D"margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204)=
;padding-left:1ex"><div dir=3D"ltr"><div class=3D"gmail_quote"><div>Miners =
will learn to create anyone-can-spend outputs to bribe other miners to buil=
d on their block rather than reorg it.=C2=A0 (Due to the coinbase maturity,=
 this will require some amount of floating capital.)<br></div></div></div><=
/blockquote><div><br></div><div>(reward=C2=A0+ avg fee) * 144 * 365 (one ye=
ar) =3D=3D approximate investment needed to reorg the chain for a double-sp=
end attack</div><div><br></div><div>in 30 years, assuming fees are still ne=
gligible (why wouldn&#39;t they be?=C2=A0 layer 2 works and layer 3 is comi=
ng), that&#39;s only 1200 bitcoin.=C2=A0 not really a lot.<br><br>there&#39=
;s only few things that allow that security budget to be ok</div><div><br><=
/div><div>=C2=A0- we assume the price goes up a lot=C2=A0</div><div><div>=
=C2=A0- we assume transactions get a lot more expensive<br></div><div><div>=
=C2=A0- we don&#39;t care about=C2=A0double-spend attacks for very large tr=
ansactions<br></div><div><br></div></div></div><div>i&#39;d rather engineer=
 block demand than ignore it</div><div><br><br><br></div></div></div>

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