Return-Path: Received: from smtp1.linuxfoundation.org (smtp1.linux-foundation.org [172.17.192.35]) by mail.linuxfoundation.org (Postfix) with ESMTPS id 3C4C0AB6 for ; Thu, 17 Nov 2016 00:10:07 +0000 (UTC) X-Greylist: whitelisted by SQLgrey-1.7.6 Received: from mail-pf0-f180.google.com (mail-pf0-f180.google.com [209.85.192.180]) by smtp1.linuxfoundation.org (Postfix) with ESMTPS id CA125254 for ; Thu, 17 Nov 2016 00:10:06 +0000 (UTC) Received: by mail-pf0-f180.google.com with SMTP id d2so45419594pfd.0 for ; Wed, 16 Nov 2016 16:10:06 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=voskuil-org.20150623.gappssmtp.com; s=20150623; h=subject:to:references:cc:from:message-id:date:user-agent :mime-version:in-reply-to; bh=e7RaiGfAlLNx0OREIXnZ+U2RVr9P1azcfTD7eHwT6nU=; b=pKxGfyXAjTIRoa37xZMLP3a7K+W5wvenWkf+Usq2SjoVb4WsQa/IrDrOzLBn/iiWPv qkd33MzfDkx5zNOY3MuSN9B03bXGzj09hEikXPcf3JH11KdyzVlxCeESIc3eWPTqDPMb Df1SqfXyFiazJN2QB6yRoU59/BIA8q/PBbivCzOD/KsIfHIOwnB+ibeYrJD3kiPsh7yl ZPganSU+OYkDkd4iNnDn+i70p5S8l3aZMk9CJDdoSMh6Fzw8azx0IDL9aknFdMmZfytg GJuwEc6cc0UsdxYO1T7w3F/7anz0aJ6fHaPFloKRFWfMqaXIeo9nro5aG4nTjkJCShL4 Dyvg== 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:cc:from:message-id:date :user-agent:mime-version:in-reply-to; bh=e7RaiGfAlLNx0OREIXnZ+U2RVr9P1azcfTD7eHwT6nU=; b=khIEYraJev8WSjkRWXOl8C9Kov4Mp3gzdHVPbrjMTXvJtJzva2eSVhx+5qGXY8CPIw xHAUJGwhCry2O/FWeJI1AETbT0CWooPAZ2470wdPpQA2iov7da73uQmtiOUoqtu80vkd IeOLaeyNbT+fNfK9eCjN7+MurOwg7n745SbNzFFvoIVaX3ESnUbBb/jgohsT1bKzs5Zd BcMgADbVRDEDehYra3hWwgh9QP8XUTtWf42eobXVNMzP3wtqiRdsNCkxKhM9hOG9NzKC R0DrOE0n6TB/UZ9h3CoroJuzeF1Uajm9O8w4d3Hii67PJwvlNHw3hVnf+RkdOHXIEor7 NZqg== X-Gm-Message-State: ABUngvdMC29Is2NBviEGd5VioM1QpKUg2pLysfqGwIPWTqgOI2rWDYsx+SViRuXuDlB6CQ== X-Received: by 10.98.57.144 with SMTP id u16mr424649pfj.142.1479341406423; Wed, 16 Nov 2016 16:10:06 -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 d1sm299994pfb.76.2016.11.16.16.10.05 (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Wed, 16 Nov 2016 16:10:05 -0800 (PST) To: =?UTF-8?Q?Jorge_Tim=c3=b3n?= References: From: Eric Voskuil Message-ID: Date: Wed, 16 Nov 2016 16:10:07 -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="3KPxTi4ERFs1aE3CfI5tgARc65aNkw5iA" X-Spam-Status: No, score=-1.9 required=5.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,RCVD_IN_DNSWL_NONE 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: Thu, 17 Nov 2016 00:12:30 +0000 Cc: Bitcoin Protocol Discussion , Thomas Kerin 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 00:10:07 -0000 This is an OpenPGP/MIME signed message (RFC 4880 and 3156) --3KPxTi4ERFs1aE3CfI5tgARc65aNkw5iA Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable No, BIP30 prevents duplicate tx hashes in the case where the new tx hash duplicates that of a preceding tx with unspent outputs. There was one such case that had already become buried in the chain at the time, so it was exempted from validation. There was another case of a duplicate hash, but it's predecessor was spent so it complied with the new rule. Both of these cases resulted from exact duplicate txs, which BIP34 now precludes. However nothing precludes different txs from having the same hash. e On 11/16/2016 04:06 PM, Jorge Tim=C3=B3n wrote: > On Thu, Nov 17, 2016 at 1:00 AM, Eric Voskuil wrote:= >> This is a misinterpretation of BIP30. Duplicate transaction hashes can= >> and will happen and are perfectly valid in Bitcoin. BIP34 does not >> prevent this. >=20 > Sorry for moving the topic, but isn't duplication of tx hashes > precisely what BIP30 prevents? > That was my undesrtanding but should read it again. > Since regular txs take inputs, the collision is extremely unlikely > (again, this is my understanding, please correct me when wrong), the > worrying case is coinbase txs (which don't have input to take entropy > from). By introducing the committed height, collisions on coinbase txs > are prevented too. >=20 > If I'm wrong on any of this I'm more than happy to learn why. >=20 --3KPxTi4ERFs1aE3CfI5tgARc65aNkw5iA 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) iQEcBAEBAgAGBQJYLPVfAAoJEDzYwH8LXOFODZcH/izM2glNTqbi6k4R6o6SiQvO PIGrJEtJAXXaJWjVRqL0CwC3CREk7gzYHsYWXH4UM7H6KYi5OReKyaU3q9Fq/VZu vaFPWI6yr4Fjateeshu5QnjzCe07lNFUlUT7Fpto3N7Js+I4QQCylCyxdxlm6+fO Qc2J45KcFN991Arn+PsTwEorx+qbjHqVua6SM21yGy3izD/JEVQV7tO7o6H88Eq1 Hei0esr+hFvfcQTGRIk7s2ZZtBRWqGid81gYWqWMexMqOafSILHOJcGetXum1Ytx rOA3DeKDPeixmu2Ryr5TfUD6kPE2SR4q5/OqnqkuT2D++qUJj1cQjVcUs8HPxow= =ifYF -----END PGP SIGNATURE----- --3KPxTi4ERFs1aE3CfI5tgARc65aNkw5iA--