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 B5DF9B75 for ; Sat, 25 Feb 2017 01:01:28 +0000 (UTC) X-Greylist: from auto-whitelisted by SQLgrey-1.7.6 Received: from outmail148101.authsmtp.com (outmail148101.authsmtp.com [62.13.148.101]) by smtp1.linuxfoundation.org (Postfix) with ESMTP id DC6DE214 for ; Sat, 25 Feb 2017 01:01:27 +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 v1P11P9H069059; Sat, 25 Feb 2017 01:01:25 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 v1P11NKk027969 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=NO); Sat, 25 Feb 2017 01:01:24 GMT Received: from [127.0.0.1] (localhost [127.0.0.1]) by petertodd.org (Postfix) with ESMTPSA id 6D3A140095; Sat, 25 Feb 2017 01:01:23 +0000 (UTC) Received: by localhost (Postfix, from userid 1000) id C700B204AB; Fri, 24 Feb 2017 20:01:22 -0500 (EST) Date: Fri, 24 Feb 2017 20:01:22 -0500 From: Peter Todd To: Steve Davis , Bitcoin Protocol Discussion Message-ID: <20170225010122.GA10233@savin.petertodd.org> References: <8F096BE1-D305-43D4-AF10-2CC48837B14F@gmail.com> MIME-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha256; protocol="application/pgp-signature"; boundary="n8g4imXOkfNTN/H1" Content-Disposition: inline In-Reply-To: <8F096BE1-D305-43D4-AF10-2CC48837B14F@gmail.com> User-Agent: Mutt/1.5.23 (2014-03-12) X-Server-Quench: ee1754e2-faf5-11e6-bcdf-0015176ca198 X-AuthReport-Spam: If SPAM / abuse - report it at: http://www.authsmtp.com/abuse X-AuthRoute: OCd2Yg0TA1ZNQRgX IjsJECJaVQIpKltL GxAVKBZePFsRUQkR aAdMdAcUHlAWAgsB AmEbW1VeUFx7W2c7 bghPaBtcak9QXgdq T0pMXVMcUgQIAB1/ fUUeUB57cQwIfHl5 bQg3C3FcWUAvd1sr ExhRCGwHMGF9OjNL Bl1YdwJRcQRMLU5E Y1gxNiYHcQ5VPz4z GA41ejw8IwAXEwR8 G0kGKlYWQF0KGTgn DxULHjhnMkwZDzsu KxorMFcWGEtZLkJ6 OEc9UFETKFcYG28W A0FMGiMcP1AbWysm FkcSW0kCWD9AWjsU GBAwJVdNCz1URiNZ AkZfUHkA 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,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 Subject: Re: [bitcoin-dev] SHA1 collisions make Git vulnerable to attakcs by third-parties, not just repo maintainers 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, 25 Feb 2017 01:01:28 -0000 --n8g4imXOkfNTN/H1 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On Fri, Feb 24, 2017 at 05:49:36PM -0600, Steve Davis via bitcoin-dev wrote: > If the 20 byte SHA1 is now considered insecure (with good reason), what a= bout RIPEMD-160 which is the foundation of Bitcoin addresses? SHA1 is insecure because the SHA1 algorithm is insecure, not because 160bit= s isn't enough. AFAIK there aren't any known weaknesses in RIPEMD160, but it also hasn't be= en as closely studied as more common hash algorithms. That said, Bitcoin uses RIPEMD160(SHA256(msg)), which may make creating collisions harder if an att= ack is found than if it used RIPEMD160 alone. --=20 https://petertodd.org 'peter'[:-1]@petertodd.org --n8g4imXOkfNTN/H1 Content-Type: application/pgp-signature; name="signature.asc" Content-Description: Digital signature -----BEGIN PGP SIGNATURE----- iQEcBAEBCAAGBQJYsNdfAAoJECSBQD2l8JH7YfYH/26iUVVHRARYVqtFpT54I+gM Qg/Cab5J+z3QZvZpIiTepnbsGlBC+UsLEfN2kT+fyqVjhj0DFW0V7dPpYq6du7rv P0ZS4GlM8Ov86TerNJhm3WGW1d5aQeAE/Idw06kDLYfheXYAQIFZPFE0tMIOFsdQ 3aiujTY0gGINXV1gVXrQJAGT38Y9tr3sOvE6ozFlKRA5Ul+y/1yyAx7DWMmBCgYo ebV3jB6GZzEXUZ7kmnxvdlBlBr08sfxtQVqC9Im4cZ0KXtEWC9HZz0/0voBuq4+4 QDRXux4aD9Nz5bgHtYuRslYL6IAVHcDMdj+lvHEx9caxGmVMyARqd78e0ZlGOc8= =6tmE -----END PGP SIGNATURE----- --n8g4imXOkfNTN/H1--