From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id D2F77C54EBD for ; Fri, 13 Jan 2023 16:10:06 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230396AbjAMQKE (ORCPT ); Fri, 13 Jan 2023 11:10:04 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:58582 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230122AbjAMQJ1 (ORCPT ); Fri, 13 Jan 2023 11:09:27 -0500 Received: from mail.turbocat.net (turbocat.net [IPv6:2a01:4f8:c17:6c4b::2]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id F1FF661302 for ; Fri, 13 Jan 2023 08:02:25 -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 3A9C426240E; Fri, 13 Jan 2023 17:02:24 +0100 (CET) Message-ID: <078526fc-7f2d-c745-a292-ff78dc06e407@selasky.org> Date: Fri, 13 Jan 2023 17:02:23 +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: rsbecker@nexbridge.com, 'Konstantin Ryabitsev' Cc: 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> <6061d012-13b7-ca4b-5556-70875b65c887@selasky.org> <00b201d92767$a0403ee0$e0c0bca0$@nexbridge.com> From: Hans Petter Selasky In-Reply-To: <00b201d92767$a0403ee0$e0c0bca0$@nexbridge.com> 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 16:56, rsbecker@nexbridge.com wrote: > git is using SHA1/SHA256 (which happen to be coincidentally cryptographic) as message digests with a very low probability of collisions when the hashes are computed. There is never a situation, implied by cryptography, where there is a decode of a git hash. In order to make git a blockchain, you would need to implement central signing authorities, which would require a fork if the signature mechanism changes. The signature mechanism (SSH, GPG) is distinct from hash computation in git's trees, but depends on hash integrity. I see. But at the same time any unique enough hash, identifies a specific piece of code or checkout, even though it is not under a specific signing authority. And that is the problem, that authorities may distribute allowed-only-hashes for their hardware ... --HPS