From mboxrd@z Thu Jan 1 00:00:00 1970 Path: news.gmane.org!not-for-mail From: Marcin Borkowski Newsgroups: gmane.emacs.help Subject: Re: A question on encryption Date: Thu, 28 Aug 2014 08:30:59 +0200 Organization: WMI UAM Message-ID: <20140828083059.199359f5@aga-netbook> References: <7zbnr5mesz.fsf@example.com> NNTP-Posting-Host: plane.gmane.org Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: quoted-printable X-Trace: ger.gmane.org 1409207494 1531 80.91.229.3 (28 Aug 2014 06:31:34 GMT) X-Complaints-To: usenet@ger.gmane.org NNTP-Posting-Date: Thu, 28 Aug 2014 06:31:34 +0000 (UTC) To: help-gnu-emacs@gnu.org Original-X-From: help-gnu-emacs-bounces+geh-help-gnu-emacs=m.gmane.org@gnu.org Thu Aug 28 08:31:28 2014 Return-path: Envelope-to: geh-help-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 1XMtEy-0006lk-NI for geh-help-gnu-emacs@m.gmane.org; Thu, 28 Aug 2014 08:31:24 +0200 Original-Received: from localhost ([::1]:34798 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1XMtEy-0007Y5-BG for geh-help-gnu-emacs@m.gmane.org; Thu, 28 Aug 2014 02:31:24 -0400 Original-Received: from eggs.gnu.org ([2001:4830:134:3::10]:35559) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1XMtEi-0007Xo-CI for help-gnu-emacs@gnu.org; Thu, 28 Aug 2014 02:31:13 -0400 Original-Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1XMtEd-0004z4-Fu for help-gnu-emacs@gnu.org; Thu, 28 Aug 2014 02:31:08 -0400 Original-Received: from msg.wmi.amu.edu.pl ([2001:808:114:2::50]:48778) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1XMtEd-0004yx-8S for help-gnu-emacs@gnu.org; Thu, 28 Aug 2014 02:31:03 -0400 Original-Received: from localhost (localhost [127.0.0.1]) by msg.wmi.amu.edu.pl (Postfix) with ESMTP id 60B4B46C97 for ; Thu, 28 Aug 2014 08:31:01 +0200 (CEST) Original-Received: from msg.wmi.amu.edu.pl ([127.0.0.1]) by localhost (msg.wmi.amu.edu.pl [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id 47l7shgL6LUC for ; Thu, 28 Aug 2014 08:31:01 +0200 (CEST) Original-Received: from aga-netbook (unknown [185.13.171.31]) by msg.wmi.amu.edu.pl (Postfix) with ESMTPSA id 26B3646C60 for ; Thu, 28 Aug 2014 08:31:01 +0200 (CEST) In-Reply-To: <7zbnr5mesz.fsf@example.com> X-Mailer: Claws Mail 3.8.1 (GTK+ 2.24.20; i686-pc-linux-gnu) X-detected-operating-system: by eggs.gnu.org: Error: Malformed IPv6 address (bad octet value). X-Received-From: 2001:808:114:2::50 X-BeenThere: help-gnu-emacs@gnu.org X-Mailman-Version: 2.1.14 Precedence: list List-Id: Users list for the GNU Emacs text editor List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: help-gnu-emacs-bounces+geh-help-gnu-emacs=m.gmane.org@gnu.org Original-Sender: help-gnu-emacs-bounces+geh-help-gnu-emacs=m.gmane.org@gnu.org Xref: news.gmane.org gmane.emacs.help:99454 Archived-At: Dnia 2014-08-28, o godz. 05:14:04 David Hume napisa=C5=82(a): > Marcin Borkowski writes: >=20 > > I created a test file (call it "test") with a single line of text > > and did two things: > > > > 1. C-x C-f test RET, C-x C-w test.gpg RET > > > > Then I selected the key and hit ok. > > > > 2. From the command line: > > gpg -e -r key-id -o test2.gpg test > > > > The two resulting files were different (difference in length of 3 > > bytes; find-file-literally and manual inspection showed that the > > beginnings were identical, but the endings were not). > > >=20 > If you encrypt the same file twice, you don't get the same encrypted > file. I think gpg will add random data to the end of the file. You > could test that theory by encrypting the same file twice using your > command line gpg. I am pretty sure I have done that in the past and > observed that I did not get the same encryption twice. Good point, that is true (which I've just checked experimentally) - thanks for pointing that out! But - the *size* remains the same (well, it did 4 times, at least). And with CLI gpg versus EPG, I also get *consistently* differences in length (by a few bytes)! Best, --=20 Marcin Borkowski http://octd.wmi.amu.edu.pl/en/Marcin_Borkowski Adam Mickiewicz University