Return-Path: Received: from smtp1.linuxfoundation.org (smtp1.linux-foundation.org [172.17.192.35]) by mail.linuxfoundation.org (Postfix) with ESMTPS id 9949BB1E for ; Thu, 17 Nov 2016 12:22:09 +0000 (UTC) X-Greylist: whitelisted by SQLgrey-1.7.6 Received: from mail-pf0-f182.google.com (mail-pf0-f182.google.com [209.85.192.182]) by smtp1.linuxfoundation.org (Postfix) with ESMTPS id 281417C for ; Thu, 17 Nov 2016 12:22:09 +0000 (UTC) Received: by mail-pf0-f182.google.com with SMTP id 189so49423452pfz.3 for ; Thu, 17 Nov 2016 04:22:09 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=voskuil-org.20150623.gappssmtp.com; s=20150623; h=subject:to:references:from:message-id:date:user-agent:mime-version :in-reply-to; bh=z4Oyufg0HcvXyRc5KuzZE39Nq+7/PDEhVbO0/LYMT9s=; b=00hrBVBmCMV2vp+Wx+7VpKqjDst9IDCjr+qM1MHhM4dbFxFU14ABQUO8uQHOLqoPBz LyWnlGo9m93rtSwtw3jk1DD8zt4uVns6mn+pbb2hRA8gGBFuvqDqSddsCrWjR8FH2rza DZ9taP0Z1zD/YmUZ3fwZFfeduEqkmsOq0R+TfFrLVIeH/H1Lp9LLWccbtEEiLl2j4Dj/ uqEr5ywoqrO4A6DcS6gT2OsUmhIwxNz7rUH/pby9i7+9oC/B10oZQtOjSdJIK6QLkUe6 QE9XXZJUKjJh661M7BhrT9fKMZOCE0Oxqe042CYAaXtDZCArGUnHKajeSix/M0EfN1eO tpbg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20130820; h=x-gm-message-state:subject:to:references:from:message-id:date :user-agent:mime-version:in-reply-to; bh=z4Oyufg0HcvXyRc5KuzZE39Nq+7/PDEhVbO0/LYMT9s=; b=DDvzo1bOnt739f67ecWWtQo3tlfhPi3xNUt+InSiy6Zl68FXtCoKyImA9GY7/Gw4gb PpazvJ7PJcFxBXkUCSVSmNighrHZwq0gB/hyjQtf0mMWxSMWF3PXKtCjtyGueZ6yBrxu R/NGoD888uXqXB8RsFV0Njkl4I9zp6GNmKG/4ACSdxYRElJOwLw320DFn5y+lspafUxE wQrEKvo0raLb2v2T1UT2fOPvS10eqVE+NgpHhHXTkbrDGZh0IpF304XPFsni9XrqvhKh ZjsxBXIgeMnSWHVBzgfydDbma8mzwEIniy+0C44x3vwyMSmEdRqYXZgJ7gghsHJYXFPL kFKQ== X-Gm-Message-State: ABUngvfSnPoFgqcuW6qlH4jWWvmK2d8T1512Dcn43BX5TmtsFIfWsBZ3mpycZNdck8cLcA== X-Received: by 10.99.107.4 with SMTP id g4mr7210207pgc.108.1479385328714; Thu, 17 Nov 2016 04:22:08 -0800 (PST) Received: from ?IPv6:2601:600:9000:d69e:8084:4206:2529:776d? ([2601:600:9000:d69e:8084:4206:2529:776d]) by smtp.gmail.com with ESMTPSA id i76sm7105970pfk.89.2016.11.17.04.22.07 (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Thu, 17 Nov 2016 04:22:07 -0800 (PST) To: Alex Morcos , Bitcoin Protocol Discussion References: <5ef23296-5909-a350-ab11-e717f8fffc41@voskuil.org> From: Eric Voskuil X-Enigmail-Draft-Status: N0110 Message-ID: <34949746-c0c9-7f14-0e92-69d5a7d44b04@voskuil.org> Date: Thu, 17 Nov 2016 04:22:09 -0800 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:45.0) Gecko/20100101 Thunderbird/45.3.0 MIME-Version: 1.0 In-Reply-To: Content-Type: multipart/signed; micalg=pgp-sha1; protocol="application/pgp-signature"; boundary="HQVQNhxjAKHdbObmF0J7vTivF7XK4A9BA" X-Spam-Status: No, score=-1.4 required=5.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID, RCVD_IN_DNSWL_NONE, RCVD_IN_SORBS_SPAM autolearn=no version=3.3.1 X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on smtp1.linux-foundation.org X-Mailman-Approved-At: Thu, 17 Nov 2016 12:53:41 +0000 Subject: Re: [bitcoin-dev] BIP30 and BIP34 interaction (was Re: [BIP Proposal] Buried Deployments) 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: Thu, 17 Nov 2016 12:22:09 -0000 This is an OpenPGP/MIME signed message (RFC 4880 and 3156) --HQVQNhxjAKHdbObmF0J7vTivF7XK4A9BA Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable On 11/17/2016 03:38 AM, Alex Morcos wrote: > I think this conversation has gone off the rails and is no longer reall= y > appropriate for the list. If this discussion is not appropriate for the Bitcoin Protocol Discussion list then the list is pointless. > But just to be clear to any readers. Bitcoin Core absolutely does rely= > on the impossibility of a hash collision for maintaining consensus.=20 > This happens in multiple places in the code but in particular we don't > check BIP30 any more since the only way it could get violated is by a > hash collision. So the protocol change that I suggested to Peter an hour or so ago was actually implemented, a year ago, by you: https://github.com/bitcoin/bitcoin/commit/06d81ad516f1d136da9f03ca2ae8232= 11c0f6988 Given that hash collisions are unquestionably possible, this is a clear break with BIP30 (irrespective of BIP34) and constitutes a hard fork. Is there going to be a retroactive BIP for this one at some point as well? I'm aware that the block hash check is performed against the full chain, as opposed to the candidate block fork height, and as a result is insufficient to guard against a block hash collision causing a chain split (though until now I assumed this was a bug). Would you care to share the other consensus critical reliances on the impossibility of hash collision that you are implying? e --HQVQNhxjAKHdbObmF0J7vTivF7XK4A9BA Content-Type: application/pgp-signature; name="signature.asc" Content-Description: OpenPGP digital signature Content-Disposition: attachment; filename="signature.asc" -----BEGIN PGP SIGNATURE----- Version: GnuPG v2.0.22 (GNU/Linux) iQEcBAEBAgAGBQJYLaDxAAoJEDzYwH8LXOFOEScH/ii9KYDI5EyYV2U1mx0dDeGI G9gvaLEq1MtaZCEaeb5USYwL05LO/kKcAg5t3xBvkpeDfoyIDKBuHkq3CKk5RlJp MEMK651aFG4QczRktOmCSEo6wYaZ0Y66U27tHoAfEfbcZsWpPPx5ado7dKHUTYz3 +rUueWE1z7qjRH52k73JQ+PBrhFCMDqH9tpx1wLK7euMy1GQxnCja7JrVXv/H1D5 r72HZsXJgvZ7R2ZfpmZ5iGJuoLhQS8GP5LEKKozD7hxttslcb+zAUAjgBCPxTYQt CV/5wVYxVUptUUXFqAYhlPKjbiiPAkkBcDP9opY+LfuWOZ7PKlsj+PSCtfSsKJ8= =KxwF -----END PGP SIGNATURE----- --HQVQNhxjAKHdbObmF0J7vTivF7XK4A9BA--