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From: Zac Greenwood <zachgrw@gmail.com>
Date: Tue, 18 May 2021 12:16:01 +0200
Message-ID: <CAJ4-pEBYJNuNMUCt5J5DbKU4RC9JXcO7gZdKh2Vq6PHCmddaeg@mail.gmail.com>
To: Bitcoin Protocol Discussion <bitcoin-dev@lists.linuxfoundation.org>, 
 ZmnSCPxj <ZmnSCPxj@protonmail.com>
Content-Type: multipart/alternative; boundary="000000000000e4334f05c297ffbe"
Cc: SatoshiSingh <SatoshiSingh@protonmail.com>
Subject: Re: [bitcoin-dev] Opinion on proof of stake in future
Precedence: list

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VDFs might enable more constant block times, for instance by having a
two-step PoW:

1. Use a VDF that takes say 9 minutes to resolve (VDF being subject to
difficulty adjustments similar to the as-is). As per the property of VDFs,
miners are able show proof of work.

2. Use current PoW mechanism with lower difficulty so finding a block takes
1 minute on average, again subject to as-is difficulty adjustments.

As a result, variation in block times will be greatly reduced.

Zac


On Tue, 18 May 2021 at 09:07, ZmnSCPxj via bitcoin-dev <
bitcoin-dev@lists.linuxfoundation.org> wrote:

> Good morning Erik,
>
> > Verifiable Delay Functions involve active participation of a single
> > verifier. Without this a VDF decays into a proof-of-work (multiple
> > verifiers === parallelism).
> >
> > The verifier, in this case is "the bitcoin network" taken as a whole.
> > I think it is reasonable to consider that some difficult-to-game
> > property of the last N blocks (like the hash of the last 100
> > block-id's or whatever), could be the verification input.
> >
> > The VDF gets calculated by every eligible proof-of-burn miner, and
> > then this is used to prevent a timing issue.
> >
> > Seems reasonable to me, but I haven't looked too far into the
> > requirements of VDF's
> >
> > nice summary for anyone who is interested:
> > https://medium.com/@djrtwo/vdfs-are-not-proof-of-work-91ba3bec2bf4
> >
> > While VDF's almost always lead to a "cpu-speed monopoly", this would
> > only be helpful for block latency in a proof-of-burn chain. Block
> > height would be calculated by eligible-miner-burned-coins, so the
> > monopoly could be easily avoided.
>
> Interesting link.
>
> However, I would like to point out that the *real* reason that PoW
> consumes lots of power is ***NOT***:
>
> * Proof-of-work is parallelizable, so it allows miners consume more energy
> (by buying more grinders) in order to get more blocks than their
> competitors.
>
> The *real* reason is:
>
> * Proof-of-work allows miners to consume more energy in order to get more
> blocks than their competitors.
>
> VDFs attempt to sidestep that by removing parallelism.
> However, there are ways to increase *sequential* speed, such as:
>
> * Overclocking.
>   * This shortens lifetime, so you can spend more energy (on building new
> miners) in order to get more blocks than your competitors.
> * Lower temperatures.
>   * This requires refrigeration/cooling, so you can spend more energy (on
> the refrigeration process) in order to get more blocks than your
> competitors.
>
> I am certain people with gaming rigs can point out more ways to improve
> sequential speed, as necessary to get more frames per second.
>
> Given the above, I think VDFs will still fail at their intended task.
> Speed, yo.
>
> Thus, VDFs do not serve as a sufficient deterrent away from
> ever-increasing energy consumption --- it just moves the energy consumption
> increase away from the obvious (parallelism) to the
> obscure-if-you-have-no-gamer-buds.
>
> You humans just need to get up to Kardashev 1.0, stat.
>
> Regards,
> ZmnSCPxj
> _______________________________________________
> bitcoin-dev mailing list
> bitcoin-dev@lists.linuxfoundation.org
> https://lists.linuxfoundation.org/mailman/listinfo/bitcoin-dev
>

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<div dir=3D"auto">VDFs might enable more constant block times, for instance=
 by having a two-step PoW:</div><div dir=3D"auto"><br></div><div dir=3D"aut=
o">1. Use a VDF that takes say 9 minutes to resolve (VDF being subject to d=
ifficulty adjustments similar to the as-is). As per the property of VDFs, m=
iners are able show proof of work.</div><div dir=3D"auto"><br></div><div di=
r=3D"auto">2. Use current PoW mechanism with lower difficulty so finding a =
block takes 1 minute on average, again subject to as-is difficulty adjustme=
nts.</div><div dir=3D"auto"><br></div><div dir=3D"auto">As a result, variat=
ion in block times will be greatly reduced.</div><div dir=3D"auto"><br></di=
v><div dir=3D"auto">Zac</div><div dir=3D"auto"><br></div><div><br><div clas=
s=3D"gmail_quote"><div dir=3D"ltr" class=3D"gmail_attr">On Tue, 18 May 2021=
 at 09:07, ZmnSCPxj via bitcoin-dev &lt;<a href=3D"mailto:bitcoin-dev@lists=
.linuxfoundation.org">bitcoin-dev@lists.linuxfoundation.org</a>&gt; wrote:<=
br></div><blockquote class=3D"gmail_quote" style=3D"margin:0px 0px 0px 0.8e=
x;border-left-width:1px;border-left-style:solid;padding-left:1ex;border-lef=
t-color:rgb(204,204,204)">Good morning Erik,<br>
<br>
&gt; Verifiable Delay Functions involve active participation of a single<br=
>
&gt; verifier. Without this a VDF decays into a proof-of-work (multiple<br>
&gt; verifiers =3D=3D=3D parallelism).<br>
&gt;<br>
&gt; The verifier, in this case is &quot;the bitcoin network&quot; taken as=
 a whole.<br>
&gt; I think it is reasonable to consider that some difficult-to-game<br>
&gt; property of the last N blocks (like the hash of the last 100<br>
&gt; block-id&#39;s or whatever), could be the verification input.<br>
&gt;<br>
&gt; The VDF gets calculated by every eligible proof-of-burn miner, and<br>
&gt; then this is used to prevent a timing issue.<br>
&gt;<br>
&gt; Seems reasonable to me, but I haven&#39;t looked too far into the<br>
&gt; requirements of VDF&#39;s<br>
&gt;<br>
&gt; nice summary for anyone who is interested:<br>
&gt; <a href=3D"https://medium.com/@djrtwo/vdfs-are-not-proof-of-work-91ba3=
bec2bf4" rel=3D"noreferrer" target=3D"_blank">https://medium.com/@djrtwo/vd=
fs-are-not-proof-of-work-91ba3bec2bf4</a><br>
&gt;<br>
&gt; While VDF&#39;s almost always lead to a &quot;cpu-speed monopoly&quot;=
, this would<br>
&gt; only be helpful for block latency in a proof-of-burn chain. Block<br>
&gt; height would be calculated by eligible-miner-burned-coins, so the<br>
&gt; monopoly could be easily avoided.<br>
<br>
Interesting link.<br>
<br>
However, I would like to point out that the *real* reason that PoW consumes=
 lots of power is ***NOT***:<br>
<br>
* Proof-of-work is parallelizable, so it allows miners consume more energy =
(by buying more grinders) in order to get more blocks than their competitor=
s.<br>
<br>
The *real* reason is:<br>
<br>
* Proof-of-work allows miners to consume more energy in order to get more b=
locks than their competitors.<br>
<br>
VDFs attempt to sidestep that by removing parallelism.<br>
However, there are ways to increase *sequential* speed, such as:<br>
<br>
* Overclocking.<br>
=C2=A0 * This shortens lifetime, so you can spend more energy (on building =
new miners) in order to get more blocks than your competitors.<br>
* Lower temperatures.<br>
=C2=A0 * This requires refrigeration/cooling, so you can spend more energy =
(on the refrigeration process) in order to get more blocks than your compet=
itors.<br>
<br>
I am certain people with gaming rigs can point out more ways to improve seq=
uential speed, as necessary to get more frames per second.<br>
<br>
Given the above, I think VDFs will still fail at their intended task.<br>
Speed, yo.<br>
<br>
Thus, VDFs do not serve as a sufficient deterrent away from ever-increasing=
 energy consumption --- it just moves the energy consumption increase away =
from the obvious (parallelism) to the obscure-if-you-have-no-gamer-buds.<br=
>
<br>
You humans just need to get up to Kardashev 1.0, stat.<br>
<br>
Regards,<br>
ZmnSCPxj<br>
_______________________________________________<br>
bitcoin-dev mailing list<br>
<a href=3D"mailto:bitcoin-dev@lists.linuxfoundation.org" target=3D"_blank">=
bitcoin-dev@lists.linuxfoundation.org</a><br>
<a href=3D"https://lists.linuxfoundation.org/mailman/listinfo/bitcoin-dev" =
rel=3D"noreferrer" target=3D"_blank">https://lists.linuxfoundation.org/mail=
man/listinfo/bitcoin-dev</a><br>
</blockquote></div></div>

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