From mboxrd@z Thu Jan 1 00:00:00 1970 Path: news.gmane.org!not-for-mail From: Nix Newsgroups: gmane.emacs.devel Subject: Re: random doesn't feel very random Date: Tue, 04 Sep 2012 21:11:35 +0100 Message-ID: <87y5kplf9k.fsf@spindle.srvr.nix> References: <876288yh72.fsf@kanis.fr> <87wr0livd4.fsf@Rainer.invalid> <83k3wfqtyx.fsf@gnu.org> <83vcfzosri.fsf@gnu.org> <5041626B.6080608@cs.ucla.edu> <87harirz13.fsf@Rainer.invalid> <50420B53.4030006@cs.ucla.edu> <87392xmw9a.fsf@spindle.srvr.nix> <50465F8D.2030706@cs.ucla.edu> NNTP-Posting-Host: plane.gmane.org Mime-Version: 1.0 Content-Type: text/plain X-Trace: ger.gmane.org 1346789505 5941 80.91.229.3 (4 Sep 2012 20:11:45 GMT) X-Complaints-To: usenet@ger.gmane.org NNTP-Posting-Date: Tue, 4 Sep 2012 20:11:45 +0000 (UTC) Cc: Achim Gratz , emacs-devel@gnu.org To: Paul Eggert Original-X-From: emacs-devel-bounces+ged-emacs-devel=m.gmane.org@gnu.org Tue Sep 04 22:11:47 2012 Return-path: Envelope-to: ged-emacs-devel@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 1T8zTO-0007VI-NF for ged-emacs-devel@m.gmane.org; Tue, 04 Sep 2012 22:11:46 +0200 Original-Received: from localhost ([::1]:47259 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1T8zTL-0001Jy-Ie for ged-emacs-devel@m.gmane.org; Tue, 04 Sep 2012 16:11:43 -0400 Original-Received: from eggs.gnu.org ([208.118.235.92]:39721) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1T8zTI-0001Jf-RK for emacs-devel@gnu.org; Tue, 04 Sep 2012 16:11:41 -0400 Original-Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1T8zTH-0006Xu-Ql for emacs-devel@gnu.org; Tue, 04 Sep 2012 16:11:40 -0400 Original-Received: from icebox.esperi.org.uk ([81.187.191.129]:43832 helo=mail.esperi.org.uk) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1T8zTH-0006XU-Gw for emacs-devel@gnu.org; Tue, 04 Sep 2012 16:11:39 -0400 Original-Received: from spindle.srvr.nix (nix@spindle.srvr.nix [192.168.14.15]) by mail.esperi.org.uk (8.14.5/8.14.5) with ESMTP id q84KBZGN012254; Tue, 4 Sep 2012 21:11:35 +0100 Emacs: because you deserve a brk today. In-Reply-To: <50465F8D.2030706@cs.ucla.edu> (Paul Eggert's message of "Tue, 04 Sep 2012 13:07:41 -0700") User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/24.1.50 (gnu/linux) X-DCC-dcc1-Metrics: spindle 1182; Body=3 Fuz1=3 Fuz2=3 X-detected-operating-system: by eggs.gnu.org: Genre and OS details not recognized. X-Received-From: 81.187.191.129 X-BeenThere: emacs-devel@gnu.org X-Mailman-Version: 2.1.14 Precedence: list List-Id: "Emacs development discussions." List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: emacs-devel-bounces+ged-emacs-devel=m.gmane.org@gnu.org Original-Sender: emacs-devel-bounces+ged-emacs-devel=m.gmane.org@gnu.org Xref: news.gmane.org gmane.emacs.devel:153018 Archived-At: On 4 Sep 2012, Paul Eggert told this: > On 09/04/2012 12:19 PM, Nix wrote: >> I'd recommend using /dev/urandom unconditionally, >> certainly for rare seeding operations > > Yes, gnulib will have a module to do that, and that's > good enough for rare operations, but it's not enough > in general. Oh, agreed. But Emacs already *has* a PRNG, and nobody is suggesting replacing it, just changing how it's seeded (and maybe making it support multiple state vectors). For a single seeding, /dev/random is quite enough. > Applications like 'shred' need lots of random > data and /dev/urandom is too slow for that. For example, Oh yes, definitely agreed. You can get random noise sources on the order of kilobits per second cheaply, but anything much faster than that requires a PRNG anyway, so /dev/random devolves into an expensive one of those. -- NULL && (void)