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Date: Wed, 11 May 2016 15:42:35 -0700
Message-ID: <CAH6h1LuemHi1Z8REhZRywghaLjAzy1e1LeHxVdA7iBifGnLnJA@mail.gmail.com>
From: Timo Hanke <timo.hanke@web.de>
To: Jannes Faber <jannes.faber@gmail.com>
Content-Type: multipart/alternative; boundary=001a11c388760c14ac053298c247
Cc: Bitcoin Protocol Discussion <bitcoin-dev@lists.linuxfoundation.org>
Subject: Re: [bitcoin-dev] Making AsicBoost irrelevant
Precedence: list

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On Wed, May 11, 2016 at 3:47 AM, Jannes Faber <jannes.faber@gmail.com>
wrote:

> On 11 May 2016 at 12:36, Henning Kopp <henning.kopp@uni-ulm.de> wrote:
>
>> On Wed, May 11, 2016 at 11:21:10AM +0200, Jannes Faber via bitcoin-dev
>> wrote:
>> > On 11 May 2016 at 05:14, Timo Hanke via bitcoin-dev <
>> > bitcoin-dev@lists.linuxfoundation.org> wrote:
>> >
>> > > There is no way to tell from a block if it was mined with AsicBoost =
or
>> > > not. So you don=E2=80=99t know what percentage of the hashrate uses =
AsicBoost
>> at
>> > > any point in time. How can you risk forking that percentage out? Not=
e
>> that
>> > > this would be a GUARANTEED chain fork. Meaning that after you change
>> the
>> > > block mining algorithm some percentage of hardware will no longer be
>> able
>> > > to produce valid blocks. That hardware cannot =E2=80=9Cswitch over=
=E2=80=9D to the
>> majority
>> > > chain even if it wanted to. Hence you are guaranteed to have two
>> > > co-existing bitcoin blockchains afterwards.
>> > >
>> > > Again: this is unlike the hypothetical persistence of two chains
>> after a
>> > > hardfork that is only contentious but doesn=E2=80=99t change the min=
ing
>> algorithm,
>> > > the kind of hardfork you are proposing would guarantee the
>> persistence of
>> > > two chains.
>> > >
>> >
>> > Assuming AsicBoost miners are in the minority, their chain will
>> constantly
>> > get overtaken. So it will not be one endless hard fork as you claim, b=
ut
>> > rather AsicBoost blocks will continue to be ignored (orphaned) until
>> they
>> > stop making them.
>>
>> At least until a difficulty adjustment on the AsicBoost chain takes
>> place. From that point on, both chains, the AsicBoost one and the
>> forked one will grow approximately at the same speed.
>>
>>
> No: you are still assuming AsicBoost miners would reject normal blocks.
> They don't now and they would have to specifically code for that as a rep=
ly
> to AsicBoost being banned. So there won't be two chains at all, only the
> main chain with a lot (more than usual) of short (few blocks) forks. Each
> forks starts anew, it's not one long fork. Therefore there is no
> "difficulty adjustment on the AiscBoost chain".
>
> Now if they do decide to ban non-AsicBoost blocks as a response to being
> banned themselves, they're just another altcoin with a different PoW and =
no
> one would have a reason to use them over Bitcoin (apart from maybe sellin=
g
> those forked coins asap).
>

This is what I meant. If existing hardware gets forked-out it will
inevitably lead to the creation of an altcoin. Simply because the hardware
exists and can't be used for anything else both chains will survive. I was
only comparing the situation to a contentious hardfork that does not fork
out any hardware. If the latter one is suspected to lead to the permanent
existence of two chains then a hardfork that forks out hardware is even
more likely to do so (I claim it's guaranteed).


> You're confused about what "longest" means as well: it's not just the
> number of blocks, it's the aggregate difficulty that counts: so AsicBoost
> would never become "longer" (more total work) either.
>
> Hope this helps clear things up.
>
> --
> Jannes
>

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<div dir=3D"ltr"><div class=3D"gmail_extra"><div class=3D"gmail_quote">On W=
ed, May 11, 2016 at 3:47 AM, Jannes Faber <span dir=3D"ltr">&lt;<a href=3D"=
mailto:jannes.faber@gmail.com" target=3D"_blank">jannes.faber@gmail.com</a>=
&gt;</span> wrote:<br><blockquote class=3D"gmail_quote" style=3D"margin:0 0=
 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><div dir=3D"ltr"><span=
 class=3D"">On 11 May 2016 at 12:36, Henning Kopp <span dir=3D"ltr">&lt;<a =
href=3D"mailto:henning.kopp@uni-ulm.de" target=3D"_blank">henning.kopp@uni-=
ulm.de</a>&gt;</span> wrote:<br></span><div class=3D"gmail_extra"><div clas=
s=3D"gmail_quote"><span class=3D""><blockquote class=3D"gmail_quote" style=
=3D"margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><span>On=
 Wed, May 11, 2016 at 11:21:10AM +0200, Jannes Faber via bitcoin-dev wrote:=
<br>
&gt; On 11 May 2016 at 05:14, Timo Hanke via bitcoin-dev &lt;<br>
&gt; <a href=3D"mailto:bitcoin-dev@lists.linuxfoundation.org" target=3D"_bl=
ank">bitcoin-dev@lists.linuxfoundation.org</a>&gt; wrote:<br>
&gt;<br>
&gt; &gt; There is no way to tell from a block if it was mined with AsicBoo=
st or<br>
&gt; &gt; not. So you don=E2=80=99t know what percentage of the hashrate us=
es AsicBoost at<br>
&gt; &gt; any point in time. How can you risk forking that percentage out? =
Note that<br>
&gt; &gt; this would be a GUARANTEED chain fork. Meaning that after you cha=
nge the<br>
&gt; &gt; block mining algorithm some percentage of hardware will no longer=
 be able<br>
&gt; &gt; to produce valid blocks. That hardware cannot =E2=80=9Cswitch ove=
r=E2=80=9D to the majority<br>
&gt; &gt; chain even if it wanted to. Hence you are guaranteed to have two<=
br>
&gt; &gt; co-existing bitcoin blockchains afterwards.<br>
&gt; &gt;<br>
&gt; &gt; Again: this is unlike the hypothetical persistence of two chains =
after a<br>
&gt; &gt; hardfork that is only contentious but doesn=E2=80=99t change the =
mining algorithm,<br>
&gt; &gt; the kind of hardfork you are proposing would guarantee the persis=
tence of<br>
&gt; &gt; two chains.<br>
&gt; &gt;<br>
&gt;<br>
&gt; Assuming AsicBoost miners are in the minority, their chain will consta=
ntly<br>
&gt; get overtaken. So it will not be one endless hard fork as you claim, b=
ut<br>
&gt; rather AsicBoost blocks will continue to be ignored (orphaned) until t=
hey<br>
&gt; stop making them.<br>
<br>
</span>At least until a difficulty adjustment on the AsicBoost chain takes<=
br>
place. From that point on, both chains, the AsicBoost one and the<br>
forked one will grow approximately at the same speed.<br>
<br></blockquote><div><br></div></span><div>No: you are still assuming Asic=
Boost miners would reject normal blocks. They don&#39;t now and they would =
have to specifically code for that as a reply to AsicBoost being banned. So=
 there won&#39;t be two chains at all, only the main chain with a lot (more=
 than usual) of short (few blocks) forks. Each forks starts anew, it&#39;s =
not one long fork. Therefore there is no &quot;difficulty adjustment on the=
 AiscBoost chain&quot;.<br><br></div><div>Now if they do decide to ban non-=
AsicBoost blocks as a response to being banned themselves, they&#39;re just=
 another altcoin with a different PoW and no one would have a reason to use=
 them over Bitcoin (apart from maybe selling those forked coins asap).<br><=
/div></div></div></div></blockquote><div><br></div><div>This is what I mean=
t. If existing hardware gets forked-out it will inevitably lead to the crea=
tion of an altcoin. Simply because the hardware exists and can&#39;t be use=
d for anything else both chains will survive. I was only comparing the situ=
ation to a contentious hardfork that does not fork out any hardware. If the=
 latter one is suspected to lead to the permanent existence of two chains t=
hen a hardfork that forks out hardware is even more likely to do so (I clai=
m it&#39;s guaranteed).</div><div><br></div><blockquote class=3D"gmail_quot=
e" style=3D"margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">=
<div dir=3D"ltr"><div class=3D"gmail_extra"><div class=3D"gmail_quote"><div=
><br></div><div>You&#39;re confused about what &quot;longest&quot; means as=
 well: it&#39;s not just the number of blocks, it&#39;s the aggregate diffi=
culty that counts: so AsicBoost would never become &quot;longer&quot; (more=
 total work) either.<br></div><br></div><div class=3D"gmail_quote">Hope thi=
s helps clear things up.<br></div><div class=3D"gmail_quote"><br>--<br></di=
v><div class=3D"gmail_quote">Jannes<br></div></div></div>
</blockquote></div><br></div></div>

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