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=-4.0 required=3.0 tests=AWL,BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,RCVD_IN_DNSWL_HI, 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 2799520133 for ; Mon, 6 Mar 2017 22:59:22 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754535AbdCFW7J (ORCPT ); Mon, 6 Mar 2017 17:59:09 -0500 Received: from mail-pf0-f181.google.com ([209.85.192.181]:35128 "EHLO mail-pf0-f181.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751073AbdCFW6z (ORCPT ); Mon, 6 Mar 2017 17:58:55 -0500 Received: by mail-pf0-f181.google.com with SMTP id j5so66278898pfb.2 for ; Mon, 06 Mar 2017 14:58:54 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20161025; h=mime-version:in-reply-to:references:from:date:message-id:subject:to :cc; bh=9xJPBOZGAiPJHQnI+JFzDUg+oOHEBz2lAMrYOwtSrpc=; b=Wg7UFjz+AXHrOzXtnOiR0e147D89tfIsNTyu55SfdhfyuLls+K8bk29I9OMt9B79ko Fsvgf505lq/2OibtJg8m3UGfhMrwEftrufLtOiuNQOqiUhOdXIMPLhDXRPH4/OcqSPnB M9RNzeUQhkwDyc/2yuW+P8ivOb4A8AoTu34SOJp32KsYYozT8bjd3l8fX0UUGopKqnKs m+Da0Jwi0xuUBOwro1CUKrnXEXqFIueZRioctKuiCNhwckx3/Ao0K/0K6RZW68rst5bI 63wVgONtCT4a4f+1qiDVRR1/U16btnyi7H7Laugc6hqaAfLr+pQ41a4KSjBzPRQ9gVCb VWlg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:in-reply-to:references:from:date :message-id:subject:to:cc; bh=9xJPBOZGAiPJHQnI+JFzDUg+oOHEBz2lAMrYOwtSrpc=; b=Q6MWz9dXCp3uMN4q6K+hCeT5Nll6N9Os06rI1W2IJyhYtHfB7qQTqpG+Ko8M3iHDoa dDqDUlD0bHDZ7yXiqQaTY/6FrBO27oM4XKpqMXOxYJ+0w9yxBcxlRdGy1b+42K3dsHEg j5lWhpml0wVYgN/Tcj3IfERPyM4wyDhajO6oV6n4hbm8k8c8ZLPDNxmM6w/qIA8AxCnQ GYw8LfGiN5orEytfH8QIw99/Ohjw6lOZVmg+8Hr/zSLJtB1Sd15fmtnA+o0bAeJELU/q DjNsYSJBGfR19mrPYFw9Fh1433CXFMjdbIYbJEA6+KauQN5VBJeIb92kbUhegIq0WsOP y1/A== X-Gm-Message-State: AMke39mK+HSQuCwJ897kxv5G4CM+uYL9MFbZXvNMSzRtpSr19dngI8UvdMKsa+Km6Wb3LTwzpp3NdzxtzCkujeJr X-Received: by 10.98.112.134 with SMTP id l128mr24162323pfc.81.1488840757575; Mon, 06 Mar 2017 14:52:37 -0800 (PST) MIME-Version: 1.0 Received: by 10.100.187.5 with HTTP; Mon, 6 Mar 2017 14:52:37 -0800 (PST) In-Reply-To: References: From: Stefan Beller Date: Mon, 6 Mar 2017 14:52:37 -0800 Message-ID: Subject: Re: [Request for Documentation] Differentiate signed (commits/tags/pushes) To: Junio C Hamano Cc: tom@oxix.org, Matthieu Moy , "git@vger.kernel.org" Content-Type: text/plain; charset=UTF-8 Sender: git-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: git@vger.kernel.org On Mon, Mar 6, 2017 at 2:13 PM, Junio C Hamano wrote: > Stefan Beller writes: > >> What is the difference between signed commits and tags? >> (Not from a technical perspective, but for the end user) > > When you "commit -s", you are signing the bytes in the commit > object, which means that you are attesting the fact that the tree > you wanted to record is one of the 47 other colliding tree objects > that happen to share that 40-hex hash value, and also the fact that > the commits you wanted to record as its parents have certain SHA-1 > hash values. As you are relying on the resistance to preimage > attack against SHA-1 at least locally around that signed commit, > there wouldn't be meaningful difference between a 50-commit series > each of which is individually signed with "commit -s", such a > 50-commit series, only the top of which is signed with "commit -s", > and the same 50-commit series, on the top of which is signed with > "tag -s". > > "tag -s" also has the benefit of being retroactive. You can create > commit, think about it for a week and then later tag it. And ask > others to also tag the same one. You cannot do so with "commit -s". ok, so there is *no* advantage of signing a commit over tags? I'll see if I can write a patch that enhances Documentation/git-commit.txt pointing to git-tag instead. >> A signed push can certify that a given payload (consisting >> of multiple commits on possibly multiple branches) was transmitted >> to a remote, which can be recorded by the remote as e.g. a proof >> of work. > > A signed push is _NOT_ about certifying the objects in the history Yes that is my understanding, though I was unclear in writing it. > I'd agree with that "checkbox" description, [...] > "commit -s" was a remedy for that. Out of curiosity: Does (did) such a project exist? Can I read up on that and their best practices? Thanks, Stefan