From: "Mark M." <markm@voicenet.com>
Date: Tue, 16 Apr 1996 10:18:52 +0800
To: "Timothy C. May" <tcmay@got.net>
Subject: Re: key bit lengths
In-Reply-To: <ad9713050002100436c2@[205.199.118.202]>
Message-ID: <Pine.LNX.3.92.960415161540.304A-100000@gak>
MIME-Version: 1.0
Content-Type: text/plain


-----BEGIN PGP SIGNED MESSAGE-----

On Sun, 14 Apr 1996, Timothy C. May wrote:

> A late April Fool's joke, methinks? Arguing that in "several billion years"
> the "temperature" of the universe will have anything to do with
> computation....well, your physics is all wrong.
>
> The approximate figure, kT, for the minimum energy in a conventional bit
> flip, can be reduced by simple cooling. Not a problem. And what the
                          ^^^^^^^^^^^^^^
> so-called "average temperature" of the Universe may be in, say, 10 billion
> years, will not affect computation. Fusion will still occur, stars will
> still burn, sunshine will still produce heat. And so on.

I'm a little rusty on physics, but it seems to me that you are forgetting the
fact that energy needs to be used in order to lower the temperature below the
temperature of background radiation.  A lot of energy.  I don't have any
numbers available, but I think that it would takes much more energy to invert
a bit where energy has to be used to keep the temperature below the temperature
of background radiation then to invert the bit at temperatures greater than or
equal to the temperature of background radiation.  Brute-force cracking will
take less energy when the universe has cooled off more (assuming it does
implode first).

- -- Mark

=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=
markm@voicenet.com              | finger -l for PGP key 0xf9b22ba5
http://www.voicenet.com/~markm/ | bd24d08e3cbb53472054fa56002258d5
"The concept of normalcy is just a conspiracy of the majority" -me

-----BEGIN PGP SIGNATURE-----
Version: 2.6.3
Charset: noconv

iQCVAwUBMXKwFbZc+sv5siulAQFv8wP/aiC93myrk4swZYJ2ocCVsvy/+HAJyu/9
ujQl910QUrs27BfkHfiHnVbTYUWQycEPxe0o4b6KGOJwkJ2TssMpuVY5TE+35GKL
a0fdaaKUxb2DDXWvr6jyOi682dLzx0gqvMo+gWXSKccFk8U5KcHZEh9TL53CopvP
2KzTet/lB0o=
=ef7j
-----END PGP SIGNATURE-----