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 DF321D58 for ; Mon, 11 Jan 2016 06:58:01 +0000 (UTC) X-Greylist: from auto-whitelisted by SQLgrey-1.7.6 Received: from outmail148113.authsmtp.com (outmail148113.authsmtp.com [62.13.148.113]) by smtp1.linuxfoundation.org (Postfix) with ESMTP id 493EAA1 for ; Mon, 11 Jan 2016 06:58:00 +0000 (UTC) Received: from mail-c247.authsmtp.com (mail-c247.authsmtp.com [62.13.128.247]) by punt22.authsmtp.com (8.14.2/8.14.2/) with ESMTP id u0B6vsCl032480; Mon, 11 Jan 2016 06:57:54 GMT Received: from petertodd.org (ec2-52-5-185-120.compute-1.amazonaws.com [52.5.185.120]) (authenticated bits=0) by mail.authsmtp.com (8.14.2/8.14.2/) with ESMTP id u0B6vqrA004769 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=NO); Mon, 11 Jan 2016 06:57:53 GMT Received: from [127.0.0.1] (localhost [127.0.0.1]) by petertodd.org (Postfix) with ESMTPSA id A44E541EDB; Mon, 11 Jan 2016 06:54:59 +0000 (UTC) In-Reply-To: <87fuy4hip0.fsf@rustcorp.com.au> References: <8760z4rbng.fsf@rustcorp.com.au> <8737u8qnye.fsf@rustcorp.com.au> <20160108153329.GA15731@sapphire.erisian.com.au> <87fuy4hip0.fsf@rustcorp.com.au> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Content-Type: text/plain; charset=UTF-8 From: Peter Todd Date: Mon, 11 Jan 2016 06:57:42 +0000 To: Rusty Russell , Rusty Russell via bitcoin-dev , Gavin Andresen , Anthony Towns Message-ID: <60A90647-86FC-49F5-9FB0-0CAA6A040A4B@petertodd.org> X-Server-Quench: a310004b-b830-11e5-bcde-0015176ca198 X-AuthReport-Spam: If SPAM / abuse - report it at: http://www.authsmtp.com/abuse X-AuthRoute: OCd2Yg0TA1ZNQRgX IjsJECJaVQIpKltL GxAVKBZePFsRUQkR bgdMdwMUElQaAgsB AmAbW1JeVVp7XGA7 bghPaBtcak9QXgdq T0pMXVMcUQUaB1pA RG8eUh11cQwIcX9x YwgzXXFbXER+J1sv Sk1UCGwHMGJ9OjNL BV1YdwJRcQRMLU5E Y1gxNiYHcQ5VPz4z GA41ejw8IwAXFCVQ T0kRKhoNRlwRD3Y1 TRcfAX1/RQgPRjl7 JBsiLl8HHUEXekwu LVIqWkl5NAVzDApC SCkA X-Authentic-SMTP: 61633532353630.1038:706 X-AuthFastPath: 0 (Was 255) X-AuthSMTP-Origin: 52.5.185.120/25 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,LOTS_OF_MONEY, 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 Subject: Re: [bitcoin-dev] Time to worry about 80-bit collision attacks or not? 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: Mon, 11 Jan 2016 06:58:02 -0000 -----BEGIN PGP SIGNED MESSAGE----- Hash: SHA512 On 10 January 2016 22:57:15 GMT-05:00, Rusty >Cheers, >Rusty. >[1] Weirdly, the bitcoin network is doing this much work every 57 > days, for about $92M. If that's all the attack costs, it's under > 1M in 10 years. Don't get too caught up in Moore's law here - more likely the attack will become feasible because SHA2 is partially weakened, as happened with SHA1. Having industry standard safety margins would make such a weakening be an academic problem rather than an emergency. -----BEGIN PGP SIGNATURE----- iQE9BAEBCgAnIBxQZXRlciBUb2RkIDxwZXRlQHBldGVydG9kZC5vcmc+BQJWk1Jc AAoJEMCF8hzn9Lncz4MH/RYReh4+oPkt8D4uW2FhiB/BlzY5Q1FP94nyi/jQAAh9 er3cUA47RhSLLd2ukC2XDgbw8CZzhnzECs7vBVsXacc3dGpzV59n8L/pnX47IRJh i1BPWHzEl/UeE/uBYUVgmy+kCVkJ80gnL2GGgZ3IXL5P+CHYY9dvhBrr53Q3HSpi aEXVivBvBnX0GeATMVY5TAiailUfsUbUmPdEHu0x5hqqTh0sUpi+R+wXWJfPESB2 hzMVZd8ALz1SJhDqbkmBNHy2CX0fhGlnMSapm6EkQksfshkcwJ7tj8s2CEOYD68T 4mR7Xh+FsOA2bbZP8M/lMd3rrXbwFzXi0rWPa70mxqI= =2W58 -----END PGP SIGNATURE-----