From mboxrd@z Thu Jan 1 00:00:00 1970 Path: news.gmane.org!not-for-mail From: "Petros Travioli" Newsgroups: gmane.emacs.bugs Subject: bug#13949: Aw: Re: bug#13949: fill-paragraph is buggy, but using MD5 is even more buggy Date: Mon, 28 Mar 2016 15:29:19 +0200 Message-ID: References: , <87r3euhozp.fsf@linux-m68k.org> NNTP-Posting-Host: plane.gmane.org Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8 X-Trace: ger.gmane.org 1459184246 30086 80.91.229.3 (28 Mar 2016 16:57:26 GMT) X-Complaints-To: usenet@ger.gmane.org NNTP-Posting-Date: Mon, 28 Mar 2016 16:57:26 +0000 (UTC) To: "Andreas Schwab" , 13949@debbugs.gnu.org Original-X-From: bug-gnu-emacs-bounces+geb-bug-gnu-emacs=m.gmane.org@gnu.org Mon Mar 28 18:57:16 2016 Return-path: Envelope-to: geb-bug-gnu-emacs@m.gmane.org Original-Received: from lists.gnu.org ([208.118.235.17]) by plane.gmane.org with esmtp (Exim 4.69) (envelope-from ) id 1akaTX-0002f9-H0 for geb-bug-gnu-emacs@m.gmane.org; Mon, 28 Mar 2016 18:57:11 +0200 Original-Received: from localhost ([::1]:41799 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1akaTW-0006Zn-5t for geb-bug-gnu-emacs@m.gmane.org; Mon, 28 Mar 2016 12:57:10 -0400 Original-Received: from eggs.gnu.org ([2001:4830:134:3::10]:43762) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1akaTR-0006ZO-Q8 for bug-gnu-emacs@gnu.org; Mon, 28 Mar 2016 12:57:06 -0400 Original-Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1akaTO-0002OB-Lt for bug-gnu-emacs@gnu.org; Mon, 28 Mar 2016 12:57:05 -0400 Original-Received: from debbugs.gnu.org ([208.118.235.43]:45141) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1akaTO-0002Ny-IQ for bug-gnu-emacs@gnu.org; Mon, 28 Mar 2016 12:57:02 -0400 Original-Received: from Debian-debbugs by debbugs.gnu.org with local (Exim 4.84_2) (envelope-from ) id 1akaTO-0007EP-D3 for bug-gnu-emacs@gnu.org; Mon, 28 Mar 2016 12:57:02 -0400 X-Loop: help-debbugs@gnu.org Resent-From: "Petros Travioli" Original-Sender: "Debbugs-submit" Resent-CC: bug-gnu-emacs@gnu.org Resent-Date: Mon, 28 Mar 2016 16:57:02 +0000 Resent-Message-ID: Resent-Sender: help-debbugs@gnu.org X-GNU-PR-Message: followup 13949 X-GNU-PR-Package: emacs X-GNU-PR-Keywords: Original-Received: via spool by 13949-submit@debbugs.gnu.org id=B13949.145918419727760 (code B ref 13949); Mon, 28 Mar 2016 16:57:02 +0000 Original-Received: (at 13949) by debbugs.gnu.org; 28 Mar 2016 16:56:37 +0000 Original-Received: from localhost ([127.0.0.1]:42266 helo=debbugs.gnu.org) by debbugs.gnu.org with esmtp (Exim 4.84_2) (envelope-from ) id 1akaSy-0007Df-8i for submit@debbugs.gnu.org; Mon, 28 Mar 2016 12:56:36 -0400 Original-Received: from mout.gmx.net ([212.227.15.19]:64128) by debbugs.gnu.org with esmtp (Exim 4.84_2) (envelope-from ) id 1akXEU-00009y-SO for 13949@debbugs.gnu.org; Mon, 28 Mar 2016 09:29:27 -0400 Original-Received: from [193.147.107.1] by 3capp-gmx-bs57.server.lan (via HTTP); Mon, 28 Mar 2016 15:29:19 +0200 Importance: normal Sensitivity: Normal In-Reply-To: <87r3euhozp.fsf@linux-m68k.org> X-UI-Message-Type: mail X-Priority: 3 X-Provags-ID: V03:K0:ur+7Af7ePJm3voV6KJg76sOJyYH4Xj3xAApUyLlEX34 ardkQ/746jKN6KIUvSoG1HkVlbRe9jMht08Fx9rIrPexyrakBD yKYc3ntsr3gYRBjbipPDVQOmztYkSpgyOtFc9cdtWr/xRaUNi6 NvZyENSUWTuLkJJsM7qhZjl9Dja9vF5e5CConxJyzbr3WMQL/Y yLFOc+PBKGkUFf4psdYlhiufDi4CH5VyGwreQGMEkc6rKGrlzw IqXhXVa0A9r5iYRgkSO8mUMuAgg5auiPCjyLgT0Kt/VWSsehiY EDwBbQ= X-UI-Out-Filterresults: notjunk:1;V01:K0:JbsjjZ9uo8E=:mu5P05HXT2DGsA6vmpxyjW a9gieC6ZG9hjODK/hnSAhtswJ+DUQ+Z/L0t6i2HNbRjaCG2ObXf3VVX0aGcvnwn1ct2ydnAlF LYon6Ae3Td6KdOca1t8cvFXEDMxHU+bbTwKesThJr7ZMA+PLQp1UWnMdUtj/2LbOiJUg5K7B0 uuiquHd0rlNR0KJ/qSclX0W9M8sxhR4gJ9L0wbQEueMb1p/pIMCpMgZW7XezcxQTvzVABiaaP ZADyXhhLVYBnNP18whr3i3CfqZ58nRUPR/gFCT4X/libfmUUmDi4nSDOIfW+NdZGnxotxL8vU nF/tVKOl//PDXZoxTPLF0c1BCpN8Kq5P27s0Fu6OoUIxN1f+a4FyR8rHnowiN7o+g6O64zpIf lWpwJGz+cdRftv6K1mT7UQovDtnVyodPfxMW+2CtztZHUh5jPs0eZ2AaeNKsaClpo/NL3UboH ZDNSxTVLEw== X-Mailman-Approved-At: Mon, 28 Mar 2016 12:56:34 -0400 X-BeenThere: debbugs-submit@debbugs.gnu.org X-Mailman-Version: 2.1.18 Precedence: list X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.2.x-3.x [generic] X-Received-From: 208.118.235.43 X-BeenThere: bug-gnu-emacs@gnu.org List-Id: "Bug reports for GNU Emacs, the Swiss army knife of text editors" List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: bug-gnu-emacs-bounces+geb-bug-gnu-emacs=m.gmane.org@gnu.org Original-Sender: bug-gnu-emacs-bounces+geb-bug-gnu-emacs=m.gmane.org@gnu.org Xref: news.gmane.org gmane.emacs.bugs:115658 Archived-At: > > But that's exactly what happens when you are using hash functions to > > verify buffer equality, just with a more complicated mathematical > > formulation and at a slightly different scale. > > > > So don't use hash functions to a two-sided correct answer to test buffer > > equality. For a one-sided answer (if hash(x) != hash(y) then x != y), you > > are fine. > > There is a difference between a hash function and a cryptographic hash > function. An inportant property of a cryptographic hash function is the > avalanche effect, that means a small change in the plaintext will result > in a big change in the hash value. That makes such a hash function > suitable for the reverse condition x != y => hash(x) != hash(y), with a > very high probability of being true. > So far most old crypto functions have been broken. There is no doubt this will happen to any newer one sooner or later. If any single person would lose his work because of a random collision, this is an argument agains crypto hash functions. I am citing RFC 6151 (https://tools.ietf.org/html/rfc6151): "MD5 is no longer acceptable where collision resistance is required..." If the developers (I think, it was Eli who embraced the patch) are so sure about collision freedom: Eli, if you are so sure about MD5, please post your password MD5 hash here with login data and a consent that anyone is allowed to hack in. I do not want to go into prison. Then wait for, say, 1 week.