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 X-Spam-Level: X-Spam-Status: No, score=-3.8 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id CEF33C4361B for ; Tue, 15 Dec 2020 02:41:46 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 822A2207A2 for ; Tue, 15 Dec 2020 02:41:46 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1725919AbgLOClY (ORCPT ); Mon, 14 Dec 2020 21:41:24 -0500 Received: from cloud.peff.net ([104.130.231.41]:60800 "EHLO cloud.peff.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725807AbgLOClG (ORCPT ); Mon, 14 Dec 2020 21:41:06 -0500 Received: (qmail 11631 invoked by uid 109); 15 Dec 2020 02:40:20 -0000 Received: from Unknown (HELO peff.net) (10.0.1.2) by cloud.peff.net (qpsmtpd/0.94) with ESMTP; Tue, 15 Dec 2020 02:40:20 +0000 Authentication-Results: cloud.peff.net; auth=none Received: (qmail 7048 invoked by uid 111); 15 Dec 2020 02:40:20 -0000 Received: from coredump.intra.peff.net (HELO sigill.intra.peff.net) (10.0.0.2) by peff.net (qpsmtpd/0.94) with (TLS_AES_256_GCM_SHA384 encrypted) ESMTPS; Mon, 14 Dec 2020 21:40:20 -0500 Authentication-Results: peff.net; auth=none Date: Mon, 14 Dec 2020 21:40:19 -0500 From: Jeff King To: "brian m. carlson" Cc: git@vger.kernel.org Subject: Re: [PATCH 0/1] Hashed mailmap support Message-ID: References: <20201213010539.544101-1-sandals@crustytoothpaste.net> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: Precedence: bulk List-ID: X-Mailing-List: git@vger.kernel.org On Mon, Dec 14, 2020 at 08:48:14PM -0500, Jeff King wrote: > On Sun, Dec 13, 2020 at 01:05:38AM +0000, brian m. carlson wrote: > > > Note that this is not perfect, because a user can simply look up all the > > hashed values and find out the old values. However, for projects which > > wish to adopt the feature, it can be somewhat effective to hash all > > existing mailmap entries and include some no-op entries from other > > contributors as well, so as to make this process less convenient. > > I remain unconvinced of the value of any noop entries. Ultimately it's > easy to invert a one-way hash that comes from a small known set of > inputs. And that's true whether there are extra noops or not. > > The interesting argument IMHO is that somebody has to _bother_ to invert > the hash. So it means that the old and new identities do not show up > next to each other in a file indexed by search engines, etc. That drops > the low-hanging fruit. > > And from that argument, I think the obvious question becomes: is it > worth using a real one-way function, as opposed to just obscuring the > raw bytes (which Ævar went into in more detail). I don't have a strong > opinion either way (the obvious one in favor is that it's less expensive > to do so; and something like "git log" will have to either compute a lot > of these hashes, or cache the hash computations internally). > > I think somebody also mentioned that there's value in the social > signaling here, and I agree with that. But that is true even for a > reversible encoding, I think. After re-reading what I wrote, I just wanted to make clear: overall the feature makes sense to me. I am questioning only the argument for it, and whether a one-way hash is the right tradeoff there. -Peff