From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from lists.gentoo.org (pigeon.gentoo.org [208.92.234.80]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by finch.gentoo.org (Postfix) with ESMTPS id 49C511396D9 for ; Tue, 24 Oct 2017 11:56:14 +0000 (UTC) Received: from pigeon.gentoo.org (localhost [127.0.0.1]) by pigeon.gentoo.org (Postfix) with SMTP id AAD2D2BC069; Tue, 24 Oct 2017 11:56:08 +0000 (UTC) Received: from smtp.gentoo.org (mail.gentoo.org [IPv6:2001:470:ea4a:1:5054:ff:fec7:86e4]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by pigeon.gentoo.org (Postfix) with ESMTPS id 5A2E5E0C47 for ; Tue, 24 Oct 2017 11:56:08 +0000 (UTC) Received: from [192.168.2.102] (ipservice-092-214-194-142.092.214.pools.vodafone-ip.de [92.214.194.142]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) (Authenticated sender: chithanh) by smtp.gentoo.org (Postfix) with ESMTPSA id B8DC433BE19 for ; Tue, 24 Oct 2017 11:56:06 +0000 (UTC) Subject: Re: [gentoo-dev] Manifest2 hashes, take n+1-th: 3 hashes for the tie-breaker case To: gentoo-dev@lists.gentoo.org References: <1508440120.19870.14.camel@gentoo.org> <26AE424C-19DF-4059-A7DE-8ED6D605FF2C@gentoo.org> <1508817879.1688.6.camel@gentoo.org> <1508818272.1688.7.camel@gentoo.org> From: =?UTF-8?Q?Ch=c3=ad-Thanh_Christopher_Nguy=e1=bb=85n?= Message-ID: <73ce6032-2c65-676c-cf5c-233810555df5@gentoo.org> Date: Tue, 24 Oct 2017 13:56:49 +0200 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:52.0) Gecko/20100101 Firefox/52.0 SeaMonkey/2.49.4.0 Precedence: bulk List-Post: List-Help: List-Unsubscribe: List-Subscribe: List-Id: Gentoo Linux mail X-BeenThere: gentoo-dev@lists.gentoo.org Reply-to: gentoo-dev@lists.gentoo.org MIME-Version: 1.0 In-Reply-To: <1508818272.1688.7.camel@gentoo.org> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit X-Archives-Salt: dfb2fda7-8144-4b34-bf88-5e3daa990023 X-Archives-Hash: 69e286452f4ae1a60d8d9343b1035971 Michał Górny schrieb: > Oh, and most notably, the speed loss will be mostly visible to users. > An attacker would have to compute the additional hashes only > if the fastest hash already matched, i.e. rarely. Users will have to > compute them all the time. That is currently the case with portage, but not an inevitable consequence of having 3 hash functions in the Manifest. Portage could be made to check only one or two of them (even by default), giving the tie-breaking ability to those who need it, and speeding up things for those who don't. Best regards, Chí-Thanh Christopher Nguyễn