From: Matt Mackall <mpm@selenic.com>
To: Theodore Tso <tytso@mit.edu>, Alan Cox <alan@lxorguk.ukuu.org.uk>,
Ray Lee <ray@madrabbit.org>, Adrian Bunk <bunk@kernel.org>,
Marc Haber <mh+linux-kernel@zugschlus.de>,
linux-kernel@vger.kernel.org
Subject: Re: Why does reading from /dev/urandom deplete entropy so much?
Date: Tue, 4 Dec 2007 14:36:36 -0600 [thread overview]
Message-ID: <20071204203636.GB19691@waste.org> (raw)
In-Reply-To: <20071204195021.GB7259@thunk.org>
On Tue, Dec 04, 2007 at 02:50:21PM -0500, Theodore Tso wrote:
> On Tue, Dec 04, 2007 at 12:02:37PM -0600, Matt Mackall wrote:
> > On Tue, Dec 04, 2007 at 04:55:02PM +0000, Alan Cox wrote:
> > > > cryptographically strong stream it'll provide when /dev/random is
> > > > tapped? In principle, this'd leave more entropy available for
> > > > applications that really need it, especially on platforms that don't
> > > > generate a lot of entropy in the first place (servers).
> > >
> > >
> > > As reported about a month ago, the evidence is that the /dev/random
> > > stream is not cryptographically strong. Collecting uuids generated from
> > > the kernel uuid random generator from the random generator in the kernel
> > > shows abnormal patterns of duplicates.
> >
> > Pointer, please.
>
> Alan, are you sure you're not talking about Helge Deller's attempt to
> push a Time-based UUID generator into the kernel because you can get
> duplicates from the current userspace library?
>
> I've not heard of *any* claim where the kernel uuid random generator
> has been returning duplicates.
Before we added proper locking, it could theoretically happen on SMP
with readers in lockstep. That was early 2.6.
The only serious critique I know of is the Gutterman-Pinkas-Reinman
paper which was a year out of date before publication. Now that
another year has passed, perhaps I should respond to it..
--
Mathematics is the supreme nostalgia of our time.
next prev parent reply other threads:[~2007-12-04 20:38 UTC|newest]
Thread overview: 77+ messages / expand[flat|nested] mbox.gz Atom feed top
2007-12-04 11:41 Why does reading from /dev/urandom deplete entropy so much? Marc Haber
2007-12-04 14:16 ` Eric Dumazet
2007-12-04 16:18 ` Adrian Bunk
2007-12-04 16:47 ` Alan Cox
2007-12-04 18:17 ` Eric Dumazet
2007-12-05 21:26 ` Matt Mackall
2007-12-06 7:02 ` Eric Dumazet
2007-12-06 16:09 ` Matt Mackall
2007-12-09 12:42 ` Marc Haber
2007-12-09 16:16 ` Matt Mackall
2007-12-10 23:06 ` Marc Haber
2007-12-10 23:35 ` Matt Mackall
2007-12-11 1:34 ` Theodore Tso
2007-12-11 19:46 ` Phillip Susi
2007-12-11 20:02 ` Ray Lee
2007-12-12 5:34 ` David Schwartz
2007-12-04 16:54 ` Ray Lee
2007-12-04 16:55 ` Alan Cox
2007-12-04 18:02 ` Matt Mackall
2007-12-04 19:50 ` Theodore Tso
2007-12-04 20:36 ` Matt Mackall [this message]
2007-12-04 20:40 ` Alan Cox
2007-12-04 20:48 ` Mike McGrath
2007-12-04 21:54 ` Matt Mackall
2007-12-04 22:03 ` Theodore Tso
2007-12-04 22:12 ` Mike McGrath
2007-12-04 22:28 ` Matt Mackall
2007-12-04 21:08 ` Matt Mackall
2007-12-04 21:18 ` Mike McGrath
2007-12-04 22:15 ` Matt Mackall
2007-12-04 22:23 ` Mike McGrath
2007-12-04 22:33 ` Matt Mackall
2007-12-05 14:26 ` Mike McGrath
2007-12-05 14:49 ` Theodore Tso
2007-12-08 7:38 ` Jon Masters
2007-12-08 17:32 ` Theodore Tso
2007-12-08 17:33 ` Mike McGrath
2007-12-08 17:49 ` Theodore Tso
2007-12-08 17:54 ` Jon Masters
2007-12-08 18:15 ` Matt Mackall
2007-12-08 18:24 ` Theodore Tso
2007-12-08 19:36 ` entropy gathering (was Re: Why does reading from /dev/urandom deplete entropy so much?) Jeff Garzik
2007-12-08 19:53 ` Matt Mackall
2007-12-08 20:04 ` Jeff Garzik
2007-12-08 20:19 ` Matt Mackall
2007-12-08 21:07 ` Willy Tarreau
2007-12-08 20:31 ` Theodore Tso
2007-12-08 20:47 ` Jeff Garzik
2007-12-08 20:42 ` Willy Tarreau
2007-12-08 23:47 ` Theodore Tso
2007-12-09 1:07 ` Jon Masters
2007-12-08 18:31 ` Why does reading from /dev/urandom deplete entropy so much? Jeff Garzik
2007-12-08 20:26 ` David Schwartz
2007-12-08 17:43 ` Matt Mackall
2007-12-08 17:47 ` Jon Masters
2007-12-08 18:05 ` Theodore Tso
2007-12-08 17:45 ` Jon Masters
2007-12-10 16:37 ` Pavel Machek
2007-12-04 18:01 ` Matt Mackall
2007-12-06 20:08 ` Bill Davidsen
2007-12-05 12:23 ` Marc Haber
2007-12-05 12:29 ` Marc Haber
2007-12-05 13:33 ` Theodore Tso
2007-12-05 15:10 ` Marc Haber
2007-12-06 19:32 ` Bill Davidsen
2007-12-08 22:03 ` Adrian Bunk
2007-12-08 22:10 ` Ismail Dönmez
2007-12-08 23:46 ` Theodore Tso
2007-12-09 5:21 ` Willy Tarreau
2007-12-09 6:52 ` Jon Masters
2007-12-09 6:21 ` Ismail Dönmez
2007-12-09 12:31 ` Theodore Tso
2007-12-09 14:06 ` Ismail Dönmez
2007-12-11 15:42 ` Bill Davidsen
2007-12-20 22:27 ` Marc Haber
2007-12-26 18:27 ` Phillip Susi
2007-12-04 18:49 ` Russ Dill
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