Return-Path: Received: from smtp1.linuxfoundation.org (smtp1.linux-foundation.org [172.17.192.35]) by mail.linuxfoundation.org (Postfix) with ESMTPS id 85DB0FA4 for ; Sat, 20 Jan 2018 06:31:30 +0000 (UTC) X-Greylist: from auto-whitelisted by SQLgrey-1.7.6 Received: from mx2.mailbox.org (mx2.mailbox.org [80.241.60.215]) by smtp1.linuxfoundation.org (Postfix) with ESMTPS id A09CE8D for ; Sat, 20 Jan 2018 06:31:29 +0000 (UTC) Received: from smtp1.mailbox.org (smtp1.mailbox.org [80.241.60.240]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mx2.mailbox.org (Postfix) with ESMTPS id 7EBF041020; Sat, 20 Jan 2018 07:31:27 +0100 (CET) X-Virus-Scanned: amavisd-new at heinlein-support.de Received: from smtp1.mailbox.org ([80.241.60.240]) by spamfilter01.heinlein-hosting.de (spamfilter01.heinlein-hosting.de [80.241.56.115]) (amavisd-new, port 10030) with ESMTP id K359Pz0RszxS; Sat, 20 Jan 2018 07:31:23 +0100 (CET) Date: Sat, 20 Jan 2018 06:30:37 +0000 From: nullius To: Jefferson Carpenter , Bitcoin Protocol Discussion Message-ID: <9bb96f6f0d4a9956def943ee3111d51b@nym.zone> References: <58fa85b8-cba3-ee34-8c96-41c6c7bfbf9c@gmail.com> <374ee97c-dae9-786f-5fc6-6fb6920360cb@gmail.com> MIME-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha512; protocol="application/pgp-signature"; boundary="q5gsqi36znq77hmw" Content-Disposition: inline In-Reply-To: <374ee97c-dae9-786f-5fc6-6fb6920360cb@gmail.com> X-Spam-Status: No, score=-2.6 required=5.0 tests=BAYES_00,RCVD_IN_DNSWL_LOW autolearn=ham version=3.3.1 X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on smtp1.linux-foundation.org X-Mailman-Approved-At: Sat, 20 Jan 2018 14:00:07 +0000 Subject: Re: [bitcoin-dev] Upgrading PoW algorithm X-BeenThere: bitcoin-dev@lists.linuxfoundation.org X-Mailman-Version: 2.1.12 Precedence: list List-Id: Bitcoin Protocol Discussion List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Sat, 20 Jan 2018 06:31:30 -0000 --q5gsqi36znq77hmw Content-Type: text/plain; charset=utf-8; format=flowed Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On 2018-01-17 at 22:31:52 +0000, Jefferson Carpenter=20 wrote: >Bitcoin's difficulty will be maxed out within about 400 years, by=20 >Moore's law. On 2018-01-19 at 20:54:52 +0000, Jefferson Carpenter=20 wrote: >In other words, max difficulty for SHA256 might be significantly faster=20 >than forcing the first 256 bits of a SHA512 hash... =E2=80=9CMoore=E2=80=99s law=E2=80=9D is not a law of nature. Indeed, chip= makers began bumping=20 up against the limitations of *actual* natural laws about 15=E2=80=9420 yea= rs=20 ago. That is why instead of increasing core clock, they play the tricks=20 which opened the way for Meltdown and Spectre. Feature size, and thus=20 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=20 number of atoms in the observable universe, I=E2=80=99ve seen estimates ran= ging=20 =66rom 10^78 to 10^82. Thus, you are suggesting that within 400 years,=20 computers will be able to compute one hash for every myriad of atoms in=20 the observable universe=E2=80=94perhaps one hash for every *ten* atoms. =20 Moreover, you suggest that twenty-fourth century computers will do this=20 fast enough to meet Bitcoin=E2=80=99s ten-minute target rate. Such a proposition bypasses science, leaps over science fiction, and=20 lands in the realm of religion. Perhaps a deity could do this=E2=80=94usin= g a=20 computer made of other than matter, powered by other than energy. =20 Humans will *never* be capable of such a feat: Not now, and not in a=20 billion years. Certainly not a mere four centuries hence! (I do not here positively exclude the possibility, however slim, that=20 mathematical breakthroughs may yield a preimage attack on SHA-256 which=20 is significantly better than bruteforce. I *do* positively declare it=20 impossible that Earth-beings will ever be capable of performing 2^256=20 work. Or even 2^128 work, for that matter.) --=20 nullius@nym.zone | PGP ECC: 0xC2E91CD74A4C57A105F6C21B5A00591B2F307E0C Bitcoin: bc1qcash96s5jqppzsp8hy8swkggf7f6agex98an7h | (Segwit nested: 3NULL3ZCUXr7RDLxXeLPDMZDZYxuaYkCnG) (PGP RSA: 0x36EBB4AB699A10EE) =E2=80=9C=E2=80=98If you=E2=80=99re not doing anything wrong, you have noth= ing to hide.=E2=80=99 No! Because I do nothing wrong, I have nothing to show.=E2=80=9D =E2=80=94= nullius --q5gsqi36znq77hmw Content-Type: application/pgp-signature; name="signature.asc" -----BEGIN PGP SIGNATURE----- iHUEARYKAB0WIQSNOMR84IlYpr/EF5vEJ5MVn575SQUCWmLiDQAKCRDEJ5MVn575 STNMAP0WsuU5Qu90mffbbEOwRnUcm2LTqdgzkH/sjIwa+NPNagEAxKJNVrvos8gj hw/j/YmUgdu9fyOuK1kx1uebqA8HUg4= =qum4 -----END PGP SIGNATURE----- --q5gsqi36znq77hmw--