From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on dcvr.yhbt.net X-Spam-Level: X-Spam-ASN: X-Spam-Status: No, score=-3.8 required=3.0 tests=AWL,BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,NICE_REPLY_A, SPF_HELO_NONE,SPF_PASS shortcircuit=no autolearn=ham autolearn_force=no version=3.4.6 Received: from out1.vger.email (out1.vger.email [IPv6:2620:137:e000::1:20]) by dcvr.yhbt.net (Postfix) with ESMTP id E86AE1F47C for ; Fri, 13 Jan 2023 16:39:53 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230040AbjAMQjB (ORCPT ); Fri, 13 Jan 2023 11:39:01 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:53786 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230511AbjAMQid (ORCPT ); Fri, 13 Jan 2023 11:38:33 -0500 Received: from mail.turbocat.net (turbocat.net [IPv6:2a01:4f8:c17:6c4b::2]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 306A6617A for ; Fri, 13 Jan 2023 08:35:58 -0800 (PST) Received: from [10.36.2.145] (unknown [46.212.121.255]) (using TLSv1.3 with cipher TLS_AES_128_GCM_SHA256 (128/128 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits)) (No client certificate requested) by mail.turbocat.net (Postfix) with ESMTPSA id 0BC492628D9; Fri, 13 Jan 2023 17:35:56 +0100 (CET) Message-ID: <038b4ea4-2a10-9b5a-14e4-e987a68e93b0@selasky.org> Date: Fri, 13 Jan 2023 17:35:57 +0100 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (X11; FreeBSD amd64; rv:102.0) Gecko/20100101 Thunderbird/102.6.1 Subject: Re: Gitorious should use CRC128 / 256 / 512 instead of SHA-1 Content-Language: en-US To: Konstantin Ryabitsev Cc: rsbecker@nexbridge.com, git@vger.kernel.org References: <39dd1a00-786b-acf5-8a40-2425f7dab6cc@selasky.org> <20230113133059.snyjblh3sz2wzcnd@carbon> <446984f6-0d2e-04da-11a3-8b1481fac953@selasky.org> <009701d9275a$678416b0$368c4410$@nexbridge.com> <8a8fbe42-7809-f3e7-b233-6bef790254e1@selasky.org> <20230113154516.jxm2cer4sogatayp@meerkat.local> <20230113160218.d3nsoxpbrxrrszhz@meerkat.local> <20230113162721.qwl2asjo542cxe3c@meerkat.local> From: Hans Petter Selasky In-Reply-To: <20230113162721.qwl2asjo542cxe3c@meerkat.local> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: git@vger.kernel.org On 1/13/23 17:27, Konstantin Ryabitsev wrote: > Not to discourage you, but you seem to be making statements without a good > understanding of how git works. If there is a history rewrite (even one that > for some reason goes back millions of commits) all hash calculations will > happen exactly once -- on the system of the person who's rewriting the > history. After they push it, it's just a bunch of objects that everyone else > merely downloads. If you used CRC, you would not need that, because CRC calculations are "concatenatable", while SHA-1's are not. CRC would just need the first and the last hash, and then you would apply the "difference". --HPS