From: Matt Mackall <mpm@selenic.com>
To: M?ns Rullg?rd <mru@users.sourceforge.net>
Cc: linux-kernel@vger.kernel.org
Subject: Re: [RFC][PATCH] Make cryptoapi non-optional?
Date: Fri, 15 Aug 2003 10:11:16 -0500 [thread overview]
Message-ID: <20030815151116.GY325@waste.org> (raw)
In-Reply-To: <yw1xfzk3pcod.fsf@users.sourceforge.net>
On Fri, Aug 15, 2003 at 10:06:42AM +0200, M?ns Rullg?rd wrote:
> Andries Brouwer <aebr@win.tue.nl> writes:
>
> >> > > entropy(x) >= entropy(x xor y)
> >> > > entropy(y) >= entropy(x xor y)
> >> >
> >> > Is this trolling? Are you serious?
> >>
> >> These lemma are absolutely true.
> >
> > David, did you read this line:
> >
> >> > Try to put z = x xor y and apply your insight to the strings x and z.
> >
> > Let us do it. Let z be an abbreviation for x xor y.
> >
> > The lemma that you believe in, applied to x and z, says
> >
> > entropy(x) >= entropy(x xor z)
> > entropy(z) >= entropy(x xor z)
> >
> > But x xor z equals y, so you believe for arbitrary strings x and y that
> >
> > entropy(x) >= entropy(y)
> > entropy(x xor y) >= entropy(y).
> >
> > This "lemma", formulated in this generality, is just plain nonsense.
>
> Not quite non-sense, but it would mean that for any strings x and y,
>
> entropy(x) == entropy(y),
>
> which seems incorrect.
No, it's a premise stated at the beginning of the thread. We're
assuming perfect distribution for x and y. The problem here is that x
and y can be dependent or independent. If they're independent, then
there's no issue. If they're dependent (for instance correlated or
anticorrelated) then x^y biases toward zero or one. Which clearly has
less entropy.
--
Matt Mackall : http://www.selenic.com : of or relating to the moon
next prev parent reply other threads:[~2003-08-15 16:12 UTC|newest]
Thread overview: 120+ messages / expand[flat|nested] mbox.gz Atom feed top
2003-08-09 7:44 [RFC][PATCH] Make cryptoapi non-optional? Matt Mackall
2003-08-09 8:04 ` David S. Miller
2003-08-09 14:05 ` Matt Mackall
2003-08-09 17:39 ` David S. Miller
2003-08-09 19:46 ` Matt Mackall
2003-08-09 20:17 ` David S. Miller
2003-08-10 8:15 ` Matt Mackall
2003-08-10 8:32 ` virt_to_offset() (Re: [RFC][PATCH] Make cryptoapi non-optional?) YOSHIFUJI Hideaki / 吉藤英明
2003-08-10 8:30 ` David S. Miller
2003-08-10 9:02 ` virt_to_offset() YOSHIFUJI Hideaki / 吉藤英明
2003-08-11 18:21 ` virt_to_offset() David Mosberger
2003-08-12 2:46 ` virt_to_offset() David S. Miller
2003-08-10 9:05 ` virt_to_offset() (Re: [RFC][PATCH] Make cryptoapi non-optional?) Matt Mackall
2003-08-10 9:04 ` David S. Miller
2003-08-10 11:00 ` [PATCH 1/9] introduce virt_to_pagoff() YOSHIFUJI Hideaki / 吉藤英明
2003-08-10 11:00 ` [PATCH 2/9] convert crypto to virt_to_pageoff() YOSHIFUJI Hideaki / 吉藤英明
2003-08-10 11:05 ` [PATCH 3/9] convert net " YOSHIFUJI Hideaki / 吉藤英明
2003-08-10 11:07 ` [PATCH 4/9] convert drivers/block " YOSHIFUJI Hideaki / 吉藤英明
2003-08-10 11:09 ` [PATCH 5/9] convert drivers/ide " YOSHIFUJI Hideaki / 吉藤英明
2003-08-10 11:10 ` [PATCH 6/9] convert drivers/net " YOSHIFUJI Hideaki / 吉藤英明
2003-08-10 11:10 ` [PATCH 7/9] convert drivers/scsi " YOSHIFUJI Hideaki / 吉藤英明
2003-08-10 11:31 ` Christoph Hellwig
2003-08-10 11:51 ` David S. Miller
2003-08-10 12:03 ` YOSHIFUJI Hideaki / 吉藤英明
2003-08-10 14:54 ` Christoph Hellwig
2003-08-10 14:51 ` Christoph Hellwig
2003-08-10 13:54 ` Russell King
2003-08-10 13:55 ` Russell King
2003-08-10 14:55 ` Christoph Hellwig
2003-08-11 5:21 ` David S. Miller
2003-08-10 11:10 ` [PATCH 8/9] convert drivers/usb " YOSHIFUJI Hideaki / 吉藤英明
2003-08-10 11:10 ` [PATCH 9/9] convert fs/jbd " YOSHIFUJI Hideaki / 吉藤英明
2003-08-11 2:15 ` [RFC][PATCH] Make cryptoapi non-optional? Jamie Lokier
2003-08-11 2:38 ` Matt Mackall
2003-08-11 4:54 ` David S. Miller
2003-08-11 5:17 ` Jamie Lokier
2003-08-13 5:01 ` [Numbers][PATCH] " Matt Mackall
2003-08-10 14:46 ` [RFC][PATCH] " James Morris
2003-08-09 14:33 ` Matt Mackall
2003-08-09 17:13 ` Jamie Lokier
2003-08-09 17:33 ` Matt Mackall
2003-08-10 13:18 ` James Morris
2003-08-10 17:45 ` Matt Mackall
2003-08-11 2:09 ` Jamie Lokier
2003-08-11 2:35 ` Matt Mackall
2003-08-11 4:59 ` Jamie Lokier
2003-08-11 5:04 ` Matt Mackall
2003-08-11 5:20 ` Jamie Lokier
2003-08-11 5:54 ` Matt Mackall
2003-08-11 6:24 ` Jamie Lokier
2003-08-11 4:58 ` David Wagner
2003-08-11 5:36 ` Jamie Lokier
2003-08-11 19:21 ` David Wagner
2003-08-13 19:37 ` Jamie Lokier
2003-08-13 3:52 ` Theodore Ts'o
2003-08-13 15:44 ` i810_rng.o on various Dell models Jim Carter
2003-08-13 16:15 ` Jeff Garzik
2003-08-13 18:43 ` Jamie Lokier
2003-08-13 18:36 ` [RFC][PATCH] Make cryptoapi non-optional? Jamie Lokier
2003-08-15 0:16 ` Network Card Entropy? was: " Mike Fedyk
2003-08-15 0:22 ` Robert Love
2003-08-13 3:20 ` Theodore Ts'o
2003-08-13 4:06 ` Matt Mackall
2003-08-14 16:53 ` Val Henson
2003-08-14 19:40 ` David Wagner
2003-08-14 20:07 ` Chris Friesen
2003-08-14 21:36 ` Jamie Lokier
2003-08-15 0:25 ` Val Henson
2003-08-15 11:47 ` Jamie Lokier
2003-08-15 0:17 ` Val Henson
2003-08-15 1:45 ` David Wagner
2003-08-15 2:21 ` Matt Mackall
2003-08-15 7:30 ` Andries Brouwer
2003-08-15 7:40 ` David S. Miller
2003-08-15 7:55 ` Andries Brouwer
2003-08-15 8:06 ` Måns Rullgård
2003-08-15 8:11 ` Nick Piggin
2003-08-15 15:11 ` Matt Mackall [this message]
2003-08-15 22:16 ` Jamie Lokier
2003-08-15 20:22 ` Val Henson
2003-08-16 6:27 ` David Wagner
2003-08-18 4:25 ` Val Henson
2003-08-15 8:09 ` Nick Piggin
2003-08-15 15:03 ` Matt Mackall
2003-08-15 17:04 ` Andries Brouwer
2003-08-15 22:05 ` Jamie Lokier
2003-08-15 22:02 ` Jamie Lokier
2003-08-15 12:48 ` Jamie Lokier
2003-08-15 22:34 ` Theodore Ts'o
2003-08-15 22:12 ` Theodore Ts'o
2003-08-15 23:35 ` James Morris
2003-08-16 15:51 ` Matt Mackall
2003-08-17 14:37 ` James Morris
2003-08-17 15:30 ` Matt Mackall
2003-08-15 23:55 ` Matt Mackall
2003-08-16 0:05 ` Andrew Morton
2003-08-16 0:58 ` Jamie Lokier
2003-08-16 4:57 ` Matt Mackall
2003-08-16 4:38 ` Matt Mackall
2003-08-16 5:03 ` Andrew Morton
2003-08-16 5:39 ` Matt Mackall
2003-08-18 6:43 ` Andreas Dilger
2003-08-18 6:55 ` David Lang
2003-08-18 11:59 ` Jamie Lokier
2003-08-18 12:11 ` Måns Rullgård
2003-08-18 13:33 ` Jamie Lokier
2003-08-18 17:03 ` David Lang
2003-08-18 17:51 ` Jamie Lokier
2003-08-22 4:28 ` David Wagner
2003-08-25 4:29 ` Jamie Lokier
2003-08-18 15:20 ` Matt Mackall
2003-08-18 3:23 ` Theodore Ts'o
2003-08-18 15:46 ` Matt Mackall
2003-08-10 2:07 ` Robert Love
2003-08-10 3:14 ` Matt Mackall
2003-08-10 3:49 ` David S. Miller
2003-08-10 4:01 ` Robert Love
2003-08-10 4:07 ` Robert Love
2003-08-16 20:40 Adam J. Richter
2003-08-17 4:28 ` Matt Mackall
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