From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from smtp1.linuxfoundation.org (smtp1.linux-foundation.org [172.17.192.35]) by mail.linuxfoundation.org (Postfix) with ESMTPS id 3F3ACB5A for ; Sat, 4 Jul 2015 03:30:26 +0000 (UTC) X-Greylist: from auto-whitelisted by SQLgrey-1.7.6 Received: from outmail149101.authsmtp.com (outmail149101.authsmtp.com [62.13.149.101]) by smtp1.linuxfoundation.org (Postfix) with ESMTP id 1578B118 for ; Sat, 4 Jul 2015 03:30:24 +0000 (UTC) Received: from mail-c235.authsmtp.com (mail-c235.authsmtp.com [62.13.128.235]) by punt15.authsmtp.com (8.14.2/8.14.2/) with ESMTP id t643UKeH037678; Sat, 4 Jul 2015 04:30:20 +0100 (BST) Received: from savin.petertodd.org (75-119-251-161.dsl.teksavvy.com [75.119.251.161]) (authenticated bits=128) by mail.authsmtp.com (8.14.2/8.14.2/) with ESMTP id t643UHpP035651 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES128-SHA bits=128 verify=NO); Sat, 4 Jul 2015 04:30:19 +0100 (BST) Date: Fri, 3 Jul 2015 23:30:16 -0400 From: Peter Todd To: Gregory Maxwell Message-ID: <20150704033016.GA14836@savin.petertodd.org> References: MIME-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha256; protocol="application/pgp-signature"; boundary="WIyZ46R2i8wDzkSu" Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.5.21 (2010-09-15) X-Server-Quench: ff5722c3-21fc-11e5-b397-002590a15da7 X-AuthReport-Spam: If SPAM / abuse - report it at: http://www.authsmtp.com/abuse X-AuthRoute: OCd2Yg0TA1ZNQRgX IjsJECJaVQIpKltL GxAVKBZePFsRUQkR aQdMdgYUEkAYAgsB AmMbW1BeU117W2M7 bA9PbARUfEhLXhtr VklWR1pVCwQmRRoF BXtmEnlydABAfX8+ ZERnWnAVChJ/ckR/ EU1JF2xQNnphaTUa TRJbfgRJcANIexZF O1F6ACIKLwdSbGoL FQ4vNDcwO3BTJTpg Ci8KN1FaRkhDHzgi ThQDEX0lGUoORD57 IwErYkIbVGwwChts eUUgXlYRLx4VDBY2 X-Authentic-SMTP: 61633532353630.1023:706 X-AuthFastPath: 0 (Was 255) X-AuthSMTP-Origin: 75.119.251.161/587 X-AuthVirus-Status: No virus detected - but ensure you scan with your own anti-virus system. 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 Cc: bitcoin-dev@lists.linuxfoundation.org Subject: Re: [bitcoin-dev] Fork of invalid blocks due to BIP66 violations X-BeenThere: bitcoin-dev@lists.linuxfoundation.org X-Mailman-Version: 2.1.12 Precedence: list List-Id: Bitcoin Development Discussion List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Sat, 04 Jul 2015 03:30:26 -0000 --WIyZ46R2i8wDzkSu Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On Sat, Jul 04, 2015 at 03:17:17AM +0000, Gregory Maxwell wrote: > On Sat, Jul 4, 2015 at 3:11 AM, Raystonn wrote: > > We need some analysis on why this has happened. It appears the larger = hashrate is violating BIP66. Thus it appears the network is rejecting this= BIP, though potentially accidentally. If this is an accident, how is such= a large portion of hashrate forking, and what can we do to avoid this in t= he future? >=20 > A near majority of the hashrate on the network appears to be SPV mining. As for what "SPV mining" is: While blocks are propagating throughout the network, frequently it's possible for miners to get the header of the block before they get and fully validate the block itself. This is just a few seconds to tens of seconds, but that's a big deal for profitability. So miners have been running custom patches that mine on top of the longest chain they know about, even if they haven't actually verified the blocks in it due to propagation delays. Unfortunately the Bitcoin protocol lets you do that, and the extra % of revenue makes a big difference when you take into account the low profit margins of mining these days. BIP66 happened to trigger this issue this time, but actually *any* miner creating an invalid block for *any* reason would have done so with the software miners are running right now. --=20 'peter'[:-1]@petertodd.org 00000000000000001242e0216eb113f1c50e4c18ecfbc8b9c0224ec82ec391d6 --WIyZ46R2i8wDzkSu Content-Type: application/pgp-signature; name="signature.asc" Content-Description: Digital signature -----BEGIN PGP SIGNATURE----- iQGrBAEBCACVBQJVl1NEXhSAAAAAABUAQGJsb2NraGFzaEBiaXRjb2luLm9yZzAw MDAwMDAwMDAwMDAwMDAxMjQyZTAyMTZlYjExM2YxYzUwZTRjMThlY2ZiYzhiOWMw MjI0ZWM4MmVjMzkxZDYvFIAAAAAAFQARcGthLWFkZHJlc3NAZ251cGcub3JncGV0 ZUBwZXRlcnRvZC5vcmcACgkQJIFAPaXwkfuT2wf9FoouftJDz+Shhck5ij3VsVdQ 1vapcropKOfqbiYEX+8Ma5WjpTttDkSHfPpQS9Q9kDQfPC9QGWFEz26FvlotDkix JiR+d7c1m1O3BNWNVTYB0n9gW2/rMFBEcsNZyhkQ4idpYeOo8cl3Amf7xctW8Nst oE5oOPUMdCWgUyd2VzCcqN68a0BgxMZqjHF0Ykbl5NEYL3C8WKwa1NPqCKfNmrPO RHLTIH7nSSIoOvXx577HDs3biBGoN/1sSQHMiK6EC9ls5uzXc5R4iUwdntLCfAGr Hy6l6QdzwaQk+NFwDtnMEgQL2cYuASOKYtTcLwZjzPdjZ3yFpalrlOBG9gy8TA== =3QuC -----END PGP SIGNATURE----- --WIyZ46R2i8wDzkSu--