Return-Path: Received: from smtp1.osuosl.org (smtp1.osuosl.org [140.211.166.138]) by lists.linuxfoundation.org (Postfix) with ESMTP id 0D932C0001 for ; Sun, 16 May 2021 21:15:34 +0000 (UTC) Received: from localhost (localhost [127.0.0.1]) by smtp1.osuosl.org (Postfix) with ESMTP id E3F0383704 for ; Sun, 16 May 2021 21:15:33 +0000 (UTC) X-Virus-Scanned: amavisd-new at osuosl.org X-Spam-Flag: NO X-Spam-Score: 0.604 X-Spam-Level: X-Spam-Status: No, score=0.604 tagged_above=-999 required=5 tests=[BAYES_50=0.8, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, FREEMAIL_FROM=0.001, HTML_FONT_FACE_BAD=0.001, HTML_FONT_LOW_CONTRAST=0.001, HTML_MESSAGE=0.001, RCVD_IN_DNSWL_NONE=-0.0001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001] autolearn=ham autolearn_force=no Authentication-Results: smtp1.osuosl.org (amavisd-new); dkim=pass (2048-bit key) header.d=gmail.com Received: from smtp1.osuosl.org ([127.0.0.1]) by localhost (smtp1.osuosl.org [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id wEBqatxHJS5o for ; Sun, 16 May 2021 21:15:32 +0000 (UTC) X-Greylist: whitelisted by SQLgrey-1.8.0 Received: from mail-il1-x135.google.com (mail-il1-x135.google.com [IPv6:2607:f8b0:4864:20::135]) by smtp1.osuosl.org (Postfix) with ESMTPS id AA55B834AE for ; Sun, 16 May 2021 21:15:32 +0000 (UTC) Received: by mail-il1-x135.google.com with SMTP id h6so4360797ila.7 for ; Sun, 16 May 2021 14:15:32 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=mime-version:references:in-reply-to:from:date:message-id:subject:to; bh=HIRwTAmxdMWkc3uXDbF2i+9vDzMnNb6TiI9J4UeCCuc=; b=M5wjNWcZwy6RewLnvGW+dcl/34apqVjVZLs3oTgd5HyeaaEJDNi+4hwDTqU4lSF7jZ KsvBLMG6GIJ53Ql6JV3gjbGgdV8vbU6s4LoZlxiPb/6WLzpQA3o16q7FUxG2B7ZSpo2Y mt2N0XagDc7r9/A967JqHD92wZ6VU0NMtBQ3yk9aZOgr3s616cZbORlwWudEdjhrV1os ak9HbiBEfqcc5FnQaWadoU3krdaBUaN8ToBUzYqC6ZNXzhhor9Uk2tlVYl8jh/g9/y3/ hj1YVoQ3gI94VKIzNNq8E7z0KLHTiHCZ0kTNp0AUY3YYqNpH/gItdjex+4IxsW5f3tAw ZJoA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to; bh=HIRwTAmxdMWkc3uXDbF2i+9vDzMnNb6TiI9J4UeCCuc=; b=idjoiA/LNpRMWA48b23TVhVT1b2p9BoVGAQDNVv/Pr5/68+agarmzvryM9mmTQjD1F i3QYF1HcUB+iUjspSfkDXNLfi+ohocwICem0s94UOsvxWxAhUe7h2CRRN/OG4dji62Y9 n1CXUv21++HV2okWs0F/bmUKzN+XnBjjblbk5tCfblKGdhe+qsHePtxi42nPKEAdJtI+ GBi580tNuDwSfanzkbeQH1gDbd8vgSvvNlXUqEl2GqQ+37+ctJhx92qlg1SJNVF0U+dU 1mBNlj+fVshiq5vXJl7JtSOl3F21Iydk+AwG+Zl1HZJm4aKS0zpRREkUh8j+8pnDoflX pbsQ== X-Gm-Message-State: AOAM5313NTK7wioEC/GO32UCBRTtp2gJdVYAzK9g2/AgDWxa3mXpyUY3 fGfkt9xokYuA1j9G/Qd2XSA7pdj40IcfowtpPyGSandc X-Google-Smtp-Source: ABdhPJz1WcKYbTTC/ZsMSAk4FqvAbkfChZ33r4UB71BR5ZjgA3GK4/EFXJj/DWsIYgr1vsxd02zwsqcGbDikLdlO7Bo= X-Received: by 2002:a92:c5ac:: with SMTP id r12mr3589021ilt.283.1621199731880; Sun, 16 May 2021 14:15:31 -0700 (PDT) MIME-Version: 1.0 References: In-Reply-To: From: Zac Greenwood Date: Sun, 16 May 2021 23:15:21 +0200 Message-ID: To: Bitcoin Protocol Discussion , Karl Content-Type: multipart/alternative; boundary="00000000000020f63e05c278fa4b" X-Mailman-Approved-At: Sun, 16 May 2021 22:02:36 +0000 Subject: Re: [bitcoin-dev] Proposal: Force to do nothing for first 9 minutes to save 90% of mining energy X-BeenThere: bitcoin-dev@lists.linuxfoundation.org X-Mailman-Version: 2.1.15 Precedence: list List-Id: Bitcoin Protocol Discussion List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Sun, 16 May 2021 21:15:34 -0000 --00000000000020f63e05c278fa4b Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable > if energy is only expended for 10% of the same duration, this money must now be spent on hardware. More equipment obviously increases the total energy usage. You correctly point out that the total expenses of a miner are not just energy but include capital expenses for equipment and operational cost for staff, rent etc. Actually, non-energy expenses are perhaps a much larger fraction of the total cost than you might expect. Miners using excess waste energy such as Chinese miners close to hydropower stations pay a near zero price for energy and are unlikely to be bound by the price of electricity. Unsurprisingly, miners having access to near-free electricity are responsible for a significant share of the total energy usage of Bitcoin. Since such energy is often waste energy from renewable sources such as hydropower, the carbon footprint of Bitcoin is not nearly as alarming as its energy usage implies. In fact, since mining is a race to the bottom in terms of cost, these large miners drive out competing miners that employ more expensive, often non-renewable sources of energy. It=E2=80=99s for ins= tance impossible to mine profitably using household-priced electricity. Looking at it from that angle, access to renewable, near-free waste energy helps keeping Bitcoin more green than it would otherwise be. To put it another way: the high energy usage of the Bitcoin network indicates cheap, otherwise wasted energy is employed. For your proposal again this means that energy usage would not be likely to decrease appreciably, because large miners having access to near-free energy use the block-reward sized budget fully on equipment and other operational expenses. On the other hand, roughly every four years the coinbase reward halves, which does significantly lower the miner budget, at least in terms of BTC. Zac On Sun, 16 May 2021 at 21:02, Karl via bitcoin-dev < bitcoin-dev@lists.linuxfoundation.org> wrote: > [sorry if I haven't replied to the other thread on this, I get swamped > by email and don't catch them all] > > This solution is workable but it seems somewhat difficult to me at this > time. > > The clock might be implementable on a peer network level by requiring > inclusion of a transaction that was broadcast after a 9 minute delay. > > Usually a 50% hashrate attack is needed to reverse a transaction in > bitcoin. With this change, this naively appears to become a 5% > hashrate attack, unless a second source of truth around time and order > is added, to verify proposed histories with. > > A 5% hashrate attack is much harder here, because the users of mining > pools would be mining only 10% of the time, so compromising mining > pools would not be as useful. > > Historically, hashrate has increased exponentially. This means that > the difficulty of performing an attack, whether it is 5% or 50%, is > still culturally infeasible because it is a multiplicative, rather > than an exponential, change. > > If this approach were to be implemented, it could be important to > consider how many block confirmations people wait for to trust their > transaction is on the chain. A lone powerful miner could > intentionally fork the chain more easily by a factor of 10. They > would need to have hashrate that competes with a major pool to do so. > > > How would you prevent miners to already compute the simpler difficulty > problem directly after the block was found and publish their solution > directly after minute 9? We would always have many people with a finished= / > competing solution. > > Such a chain would have to wait a longer time to add further blocks > and would permanently be shorter. > > > Your proposal won=E2=80=99t save any energy because it does nothing to = decrease > the budget available to mine a block (being the block reward). > > You are assuming this budget is directly related to energy > expenditure, but if energy is only expended for 10% of the same > duration, this money must now be spent on hardware. The supply of > bitcoin hardware is limited. > > In the long term, it won't be, so a 10% decrease is a stop-gap > measure. Additionally, in the long term, we will have quantum > computers and AI-designed cryptography algorithms, so things will be > different in a lot of other ways too. > _______________________________________________ > bitcoin-dev mailing list > bitcoin-dev@lists.linuxfoundation.org > https://lists.linuxfoundation.org/mailman/listinfo/bitcoin-dev > --00000000000020f63e05c278fa4b Content-Type: text/html; charset="UTF-8" Content-Transfer-Encoding: quoted-printable
> if energy is only expended fo= r 10% of the same=C2=A0duration, this money must now be spent on hardware.

More equipment obviously increases the total energy usage.

You correctly point out that the total expenses of= a miner are not just energy but include capital expenses for equipment and= operational cost for staff, rent etc.

Actually, no= n-energy expenses are perhaps a much larger fraction of the total cost than= you might expect. Miners using excess waste energy such as Chinese miners = close to hydropower stations pay a near zero price for energy and are unlik= ely to be bound by the price of electricity.

Unsurprisingly, miners having a= ccess to near-free electricity are responsible for a significant share of t= he total energy usage of Bitcoin. Since such energy is often waste energy f= rom renewable sources such as hydropower, the carbon footprint of Bitcoin i= s not nearly as alarming as its energy usage implies.=C2=A0In fact, since mining is a race to th= e bottom in terms of cost, these large miners drive out competing miners th= at employ more expensive, often non-renewable sources of energy. It=E2=80= =99s for instance impossible to mine profitably using household-priced elec= tricity. Looking at it from that angle, access to renewable, near-free wast= e energy helps keeping Bitcoin more green than it would otherwise be. To pu= t it another way: the high energy usage of the Bitcoin network indicates ch= eap, otherwise wasted energy is employed.

For your proposal again thi= s means that energy usage would not be likely to decrease appreciably, beca= use large miners having access to near-free energy use the block-reward siz= ed budget fully on equipment and other operational expenses.

On the other hand, roughly every four years the coinbase reward h= alves, which does significantly lower the miner budget, at least in terms o= f BTC.

=
Zac



On Sun, 16 May 2021 at 21:02, Karl via bitcoin-dev <bitcoin-dev@lists.linuxfoundation.o= rg> wrote:
[sorry if I haven't replied= to the other thread on this, I get swamped
by email and don't catch them all]

This solution is workable but it seems somewhat difficult to me at this tim= e.

The clock might be implementable on a peer network level by requiring
inclusion of a transaction that was broadcast after a 9 minute delay.

Usually a 50% hashrate attack is needed to reverse a transaction in
bitcoin.=C2=A0 With this change, this naively appears to become a 5%
hashrate attack, unless a second source of truth around time and order
is added, to verify proposed histories with.

A 5% hashrate attack is much harder here, because the users of mining
pools would be mining only 10% of the time, so compromising mining
pools would not be as useful.

Historically, hashrate has increased exponentially.=C2=A0 This means that the difficulty of performing an attack, whether it is 5% or 50%, is
still culturally infeasible because it is a multiplicative, rather
than an exponential, change.

If this approach were to be implemented, it could be important to
consider how many block confirmations people wait for to trust their
transaction is on the chain.=C2=A0 A lone powerful miner could
intentionally fork the chain more easily by a factor of 10.=C2=A0 They
would need to have hashrate that competes with a major pool to do so.

> How would you prevent miners to already compute the simpler difficulty= problem directly after the block was found and publish their solution dire= ctly after minute 9? We would always have many people with a finished / com= peting solution.

Such a chain would have to wait a longer time to add further blocks
and would permanently be shorter.

> Your proposal won=E2=80=99t save any energy because it does nothing to= decrease the budget available to mine a block (being the block reward).
You are assuming this budget is directly related to energy
expenditure, but if energy is only expended for 10% of the same
duration, this money must now be spent on hardware.=C2=A0 The supply of
bitcoin hardware is limited.

In the long term, it won't be, so a 10% decrease is a stop-gap
measure.=C2=A0 Additionally, in the long term, we will have quantum
computers and AI-designed cryptography algorithms, so things will be
different in a lot of other ways too.
_______________________________________________
bitcoin-dev mailing list
= bitcoin-dev@lists.linuxfoundation.org
https://lists.linuxfoundation.org/mail= man/listinfo/bitcoin-dev
--00000000000020f63e05c278fa4b--