From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on dcvr.yhbt.net X-Spam-Level: X-Spam-ASN: AS31976 209.132.180.0/23 X-Spam-Status: No, score=-3.0 required=3.0 tests=AWL,BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,RCVD_IN_DNSWL_HI,T_RP_MATCHES_RCVD shortcircuit=no autolearn=ham autolearn_force=no version=3.4.0 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by dcvr.yhbt.net (Postfix) with ESMTP id 9401F209FD for ; Tue, 6 Jun 2017 22:45:32 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751471AbdFFWpa (ORCPT ); Tue, 6 Jun 2017 18:45:30 -0400 Received: from mail-pf0-f193.google.com ([209.85.192.193]:36792 "EHLO mail-pf0-f193.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751424AbdFFWp3 (ORCPT ); Tue, 6 Jun 2017 18:45:29 -0400 Received: by mail-pf0-f193.google.com with SMTP id y7so6990807pfd.3 for ; Tue, 06 Jun 2017 15:45:29 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=date:from:to:cc:subject:message-id:references:mime-version :content-disposition:in-reply-to:user-agent; bh=NBA+iZpAQHjRNA+F5JDhYDsMpSBMKJXx18CkkWKFQ20=; b=MO6aEtsrgLpRnOu59acZ6Y3Pf21MtunNtp07lR71hOeazYGEjwf82/oEoiD2DmfEpV on0sW8f5gXJN+sw72wuNmQ861Mx4CNhvzDOHC7YtK23T0KTjglJzWLWom21RgD+g/8r+ VExkuHZJTJUyjOkfDjcpwQwsy7QJwqx9QVIYCRSxVSwoXOUpgIf+lAjm4ATnRz7AhqYz k+xwVphJHa+muCVEwtH6Jf+TvaY0lnQ7AR9jX2y54qNkUeaRd5pkbj5+bfhhnulrbNmP fVDYpvNmj9Il9MrSM+e7VoH2SIJTnJDg3eVibkljUpU+LVJT3KGTfx+RZEMI2m+7ptX1 kvmA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:from:to:cc:subject:message-id:references :mime-version:content-disposition:in-reply-to:user-agent; bh=NBA+iZpAQHjRNA+F5JDhYDsMpSBMKJXx18CkkWKFQ20=; b=cGw1HxpqV4FIZLrG4RgVTX+pUcxvNKvuftI1vH621hDTYv/zWIX3vWc71Go+UV55Lk T1M55rjBD4uCxGMOedAXeh1LfPF9v0m9mdkOAMz+JrYm5+ylgRTWj+/2DKm+kh7qR898 nUGWaY/vLfKnhepFQ2RBj/rwRZ706nYn9le4b+h9P0SOvnyTaFZl0F1bPrilx0REEDsd NMZTxXNhZ24uRJHCuAhB1OlOzTAYCikVXl8aud4rlJ6S3fghelfbVgJ8V9EQjCq8Tkyn 24m9jPje/9KYRTbGWG1ZAfJfwSu7woeqcPHGOXHu+TErLKaWD46LMxM2z+Nc8ldvxw3R AUkA== X-Gm-Message-State: AODbwcC+oz81lYgAJzQwHGbZ7wVB4UoBaZAnj9/HdlQNQwV1BOVFHTkQ 9NBc11KDLxJ9zw== X-Received: by 10.98.109.2 with SMTP id i2mr13498467pfc.186.1496789128383; Tue, 06 Jun 2017 15:45:28 -0700 (PDT) Received: from aiede.mtv.corp.google.com ([2620:0:100e:402:5be:2d73:26a4:30ee]) by smtp.gmail.com with ESMTPSA id g13sm25721013pgu.54.2017.06.06.15.45.26 (version=TLS1_2 cipher=AES128-SHA bits=128/128); Tue, 06 Jun 2017 15:45:26 -0700 (PDT) Date: Tue, 6 Jun 2017 15:45:24 -0700 From: Jonathan Nieder To: Johannes Schindelin Cc: Stefan Beller , Junio C Hamano , Phillip Wood , "git@vger.kernel.org" , =?iso-8859-1?Q?=C6var_Arnfj=F6r=F0?= Bjarmason Subject: Re: pushing for a new hash, was Re: [PATCH 2/3] rebase: Add tests for console output Message-ID: <20170606224524.GC21733@aiede.mtv.corp.google.com> References: <20170531104213.16944-1-phillip.wood@talktalk.net> <20170531104213.16944-3-phillip.wood@talktalk.net> <20170602175455.GA30988@aiede.mtv.corp.google.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.5.21 (2010-09-15) Sender: git-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: git@vger.kernel.org Hi, Johannes Schindelin wrote: > On Fri, 2 Jun 2017, Jonathan Nieder wrote: >> Johannes Schindelin wrote: >>> Maybe we should call out a specific month (or even a longer period) during >>> which we try to push toward that new hash function, and focus more on >>> those tasks (and on critical bug fixes, if any) than anything else. >> >> Thanks for offering. ;-) > > Undoubtedly my lack of command of the English language is to blame for > this misunderstanding. > > By no means did I try to indicate that I am ready to accept the > responsibility of working toward a new hash dumped on me. It was a joke. More seriously, I do appreciate your questions to get this discussion going. [...] > 3) the only person who could make that call is Junio I strongly disagree with this. > 4) we still have the problem that there is no cryptography expert among > those who in the Git project are listened to *shrug* I still don't know what you are suggesting here. Are you saying we should find a cryptography expert to pay? Or do you have other specific suggestions of how to attract them? >> How did you get the impression that their opinion had no impact? We have >> been getting feedback about the choice of hash function both on and off >> list from a variety of people, some indisputably security experts. >> Sometimes the best one can do is to just listen. > > I did get the impression by talking at length to a cryptography expert who > successfully resisted any suggestions to get involved in the Git mailing > list. I know of other potential Git contributors that have resisted getting involved in the Git mailing list, too. I still don't know what you are suggesting here. Forgive me for being dense. > There were also accounts floating around on Twitter that a certain > cryptography expert who dared to mention already back in 2005 how > dangerous it would be to hardcode SHA-1 into Git was essentially shown the > finger, and I cannot fault him for essentially saying "I told you so" > publicly. I think there is a concrete suggestion embedded here: when discussions go in an unproductive direction, my usual practice has been to keep away from them. This means that to a casual observer there can appear to be a consensus that doesn't really exist. We need to do better than that: when a prominent contributor like Linus and people newer to the project are emphatically dismissing the security impact of using a broken hash function, others in the project need to speak up to make it clear that those are not the actual opinions of the project. To put it another way: "The standard you walk past is the standard you accept". I have failed at this. It is a very hard problem to solve, but it is worth solving. > In my mind, it would have made sense to ask well-respected cryptographers > about their opinions and then try to figure out a consensus among them (as > opposed to what I saw so far, a lot of enthusastic talk by developers with > little standing in the cryptography community, mostly revolving around > hash size and speed as opposed to security). And then try to implement > that consensus in Git. Given my recent success rate with SHA-1 related > concerns, I am unfortunately not the person who can bring that about. > > But maybe you are. I think you are being a bit dismissive of both the work done so far and the value of your own work. I am happy to solicit more input from security researchers, though, and your suggestion to do so is good advice. Thanks and hope that helps, Jonathan