From: nullius <nullius@nym•zone>
To: Jefferson Carpenter <jeffersoncarpenter2@gmail•com>,
Bitcoin Protocol Discussion
<bitcoin-dev@lists•linuxfoundation.org>
Subject: Re: [bitcoin-dev] Upgrading PoW algorithm
Date: Sat, 20 Jan 2018 06:30:37 +0000 [thread overview]
Message-ID: <9bb96f6f0d4a9956def943ee3111d51b@nym.zone> (raw)
In-Reply-To: <374ee97c-dae9-786f-5fc6-6fb6920360cb@gmail.com>
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On 2018-01-17 at 22:31:52 +0000, Jefferson Carpenter
<jeffersoncarpenter2@gmail•com> wrote:
>Bitcoin's difficulty will be maxed out within about 400 years, by
>Moore's law.
On 2018-01-19 at 20:54:52 +0000, Jefferson Carpenter
<jeffersoncarpenter2@gmail•com> wrote:
>In other words, max difficulty for SHA256 might be significantly faster
>than forcing the first 256 bits of a SHA512 hash...
“Moore’s law” is not a law of nature. Indeed, chipmakers began bumping
up against the limitations of *actual* natural laws about 15—20 years
ago. That is why instead of increasing core clock, they play the tricks
which opened the way for Meltdown and Spectre. Feature size, and thus
transistor counts, will soon enough run into physical limitations, too.
But the scenario you describe does not even require such a discussion.
2^256 work for brute force is on the order of 10^77 hashes. For the
number of atoms in the observable universe, I’ve seen estimates ranging
from 10^78 to 10^82. Thus, you are suggesting that within 400 years,
computers will be able to compute one hash for every myriad of atoms in
the observable universe—perhaps one hash for every *ten* atoms.
Moreover, you suggest that twenty-fourth century computers will do this
fast enough to meet Bitcoin’s ten-minute target rate.
Such a proposition bypasses science, leaps over science fiction, and
lands in the realm of religion. Perhaps a deity could do this—using a
computer made of other than matter, powered by other than energy.
Humans will *never* be capable of such a feat: Not now, and not in a
billion years. Certainly not a mere four centuries hence!
(I do not here positively exclude the possibility, however slim, that
mathematical breakthroughs may yield a preimage attack on SHA-256 which
is significantly better than bruteforce. I *do* positively declare it
impossible that Earth-beings will ever be capable of performing 2^256
work. Or even 2^128 work, for that matter.)
--
nullius@nym•zone | PGP ECC: 0xC2E91CD74A4C57A105F6C21B5A00591B2F307E0C
Bitcoin: bc1qcash96s5jqppzsp8hy8swkggf7f6agex98an7h | (Segwit nested:
3NULL3ZCUXr7RDLxXeLPDMZDZYxuaYkCnG) (PGP RSA: 0x36EBB4AB699A10EE)
“‘If you’re not doing anything wrong, you have nothing to hide.’
No! Because I do nothing wrong, I have nothing to show.” — nullius
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next prev parent reply other threads:[~2018-01-20 6:31 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-01-17 22:31 Jefferson Carpenter
2018-01-18 16:36 ` Peter Todd
2018-01-19 20:54 ` Jefferson Carpenter
2018-01-20 6:30 ` nullius [this message]
2018-01-20 18:36 ` Melvin Carvalho
2018-01-21 15:29 ` Glen Peterson
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