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Date: Wed, 31 Dec 2014 13:25:41 -0500
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From: Stephen Morse <stephencalebmorse@gmail.com>
To: Gregory Maxwell <gmaxwell@gmail.com>
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Cc: bitcoin-development <bitcoin-development@lists.sourceforge.net>
Subject: Re: [Bitcoin-development] BIP: Voluntary deposit bonds
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I agree with Gregory Maxwell, I don't think it would be as easy as just
changing IsCoinBase(), since there are places where the code assumes that
the coinbase's vin doesn't spend any prevouts and/or has size 1. For
example, here
<https://github.com/bitcoin/bitcoin/blob/v0.9.3/src/main.cpp#L617-620> and
here <https://github.com/bitcoin/bitcoin/blob/v0.9.3/src/main.cpp#L785-L808>
.

I think the motivation behind the original suggestion is to have a way to
pay specific miners upon solving a block without risking possibly paying
other miners through pay-to-fee. What I'm not sure about, though, is why
not just send them a transaction once you see that the miner has solved a
block? Not a pay-to-fee transaction, a pay to pubkeyhash or whatever type
of transaction you need to make to send the miner some coins.

Although I don't completely understand the motivation for making such
transactions, maybe this would this work. Have outputs in the coinbase
transaction which have nValue == 0, then only apply the COINBASE_MATURITY
rule to spending coinbase outputs which have non-zero value. That way you
could make a transactions which is only valid after the miner specified
solves a block with the coinbase having the same TxID referenced by the new
transaction's input. It's still a hard fork, but might be easier than
allowing the coinbase to spend prevouts. I guess, at that point though, why
not just hard fork to allow the coinbase to spend prevouts...

Best,
Stephen

On Tue, Dec 30, 2014 at 1:28 PM, Gregory Maxwell <gmaxwell@gmail.com> wrote:

> On Tue, Dec 30, 2014 at 4:25 PM, Sergio Lerner
> <sergiolerner@certimix.com> wrote:
> > Slight off-topic:
> > That looks like an abuse of the VM. Even P2SH is an abuse of the VM.
> > Gavin's OP_EVAL (hard-fork) should had been chosen. I'm taking about a
> > simple change that goes along the lines of Satoshi's original design.
> > Bitcoin was a beautiful design, and extra complexity is making it ugly.
> > We need Bitcoin to be simple to understand for new programmers so they
> > can keep the project going. It doesn't help the project that one needs
> > to be a guru to code for Bitcoin.
>
> Sergio there is no "abuse" there,  OP_NOP3 in that case would be
> redefined to OP_COINBASE_FOO_CONSISTENCY.
>
> (I say FOO because it's not clear what rule you actually hope to apply
> there.)
>
> What you suggested has no purpose by itself: it would need an
> additional change which overlays functionality in order to actually do
> something. Such a change would likely be "ugly"-- it's easy to be
> elegant when you do nothing.
>
>
> ------------------------------------------------------------------------------
> Dive into the World of Parallel Programming! The Go Parallel Website,
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> your
> hub for all things parallel software development, from weekly thought
> leadership blogs to news, videos, case studies, tutorials and more. Take a
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--f46d0435c61425619c050b873c66
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<div dir=3D"ltr">I agree with Gregory Maxwell, I don&#39;t think it would b=
e as easy as just changing IsCoinBase(), since there are places where the c=
ode assumes that the coinbase&#39;s vin doesn&#39;t spend any prevouts and/=
or has size 1. For example, <a href=3D"https://github.com/bitcoin/bitcoin/b=
lob/v0.9.3/src/main.cpp#L617-620">here</a>=C2=A0and <a href=3D"https://gith=
ub.com/bitcoin/bitcoin/blob/v0.9.3/src/main.cpp#L785-L808">here</a>.=C2=A0<=
div><br><div>I think the motivation behind the original suggestion is to ha=
ve a way to pay specific miners upon solving a block without risking possib=
ly paying other miners through pay-to-fee. What I&#39;m not sure about, tho=
ugh, is why not just send them a transaction once you see that the miner ha=
s solved a block? Not a pay-to-fee transaction, a pay to pubkeyhash or what=
ever type of transaction you need to make to send the miner some coins.<div=
><div><br></div><div>Although I don&#39;t completely understand the motivat=
ion for making such transactions, maybe this would this work. Have outputs =
in the coinbase transaction which have nValue =3D=3D 0, then only apply the=
 COINBASE_MATURITY rule to spending coinbase outputs which have non-zero va=
lue. That way you could make a transactions which is only valid after the m=
iner specified solves a block with the coinbase having the same TxID refere=
nced by the new transaction&#39;s input. It&#39;s still a hard fork, but mi=
ght be easier than allowing the coinbase to spend prevouts. I guess, at tha=
t point though, why not just hard fork to allow the coinbase to spend prevo=
uts...</div><div><br></div><div>Best,</div><div>Stephen</div></div></div></=
div></div><div class=3D"gmail_extra"><br><div class=3D"gmail_quote">On Tue,=
 Dec 30, 2014 at 1:28 PM, Gregory Maxwell <span dir=3D"ltr">&lt;<a href=3D"=
mailto:gmaxwell@gmail.com" target=3D"_blank">gmaxwell@gmail.com</a>&gt;</sp=
an> wrote:<br><blockquote class=3D"gmail_quote" style=3D"margin:0 0 0 .8ex;=
border-left:1px #ccc solid;padding-left:1ex"><span class=3D"">On Tue, Dec 3=
0, 2014 at 4:25 PM, Sergio Lerner<br>
&lt;<a href=3D"mailto:sergiolerner@certimix.com">sergiolerner@certimix.com<=
/a>&gt; wrote:<br>
&gt; Slight off-topic:<br>
&gt; That looks like an abuse of the VM. Even P2SH is an abuse of the VM.<b=
r>
&gt; Gavin&#39;s OP_EVAL (hard-fork) should had been chosen. I&#39;m taking=
 about a<br>
&gt; simple change that goes along the lines of Satoshi&#39;s original desi=
gn.<br>
&gt; Bitcoin was a beautiful design, and extra complexity is making it ugly=
.<br>
&gt; We need Bitcoin to be simple to understand for new programmers so they=
<br>
&gt; can keep the project going. It doesn&#39;t help the project that one n=
eeds<br>
&gt; to be a guru to code for Bitcoin.<br>
<br>
</span>Sergio there is no &quot;abuse&quot; there,=C2=A0 OP_NOP3 in that ca=
se would be<br>
redefined to OP_COINBASE_FOO_CONSISTENCY.<br>
<br>
(I say FOO because it&#39;s not clear what rule you actually hope to apply =
there.)<br>
<br>
What you suggested has no purpose by itself: it would need an<br>
additional change which overlays functionality in order to actually do<br>
something. Such a change would likely be &quot;ugly&quot;-- it&#39;s easy t=
o be<br>
elegant when you do nothing.<br>
<div class=3D"HOEnZb"><div class=3D"h5"><br>
---------------------------------------------------------------------------=
---<br>
Dive into the World of Parallel Programming! The Go Parallel Website,<br>
sponsored by Intel and developed in partnership with Slashdot Media, is you=
r<br>
hub for all things parallel software development, from weekly thought<br>
leadership blogs to news, videos, case studies, tutorials and more. Take a<=
br>
look and join the conversation now. <a href=3D"http://goparallel.sourceforg=
e.net" target=3D"_blank">http://goparallel.sourceforge.net</a><br>
_______________________________________________<br>
Bitcoin-development mailing list<br>
<a href=3D"mailto:Bitcoin-development@lists.sourceforge.net">Bitcoin-develo=
pment@lists.sourceforge.net</a><br>
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" target=3D"_blank">https://lists.sourceforge.net/lists/listinfo/bitcoin-de=
velopment</a><br>
</div></div></blockquote></div><br></div>

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