[4114] in cryptography@c2.net mail archive
Re:
daemon@ATHENA.MIT.EDU (Clive D.W. Feather)
Mon Feb 1 20:53:44 1999
Date: Sat, 30 Jan 1999 15:45:58 -0800
To: cryptography@c2.net
From: "Clive D.W. Feather" <clive@on-the-train.demon.co.uk>
Reply-To: "Clive D.W. Feather" <clive@davros.org>
In-Reply-To: <199901281606.LAA25185@pollen.cs.concordia.ca>
In article <199901281606.LAA25185@pollen.cs.concordia.ca>, MCKAY john
<mckay@cs.concordia.ca> writes
>Another curiosity of the Mark I's instruction set was a sideways
>add ('population count'), also specified by Turing. I've always
>assumed that the two instructions could be useful for cryptography -
Think about how the Bombes worked. You injected signal into one line,
and wanted to know when it didn't come back on all of the other 25. A
software implementation of this could use a population count to
advantage.
--
Clive D.W. Feather | Director of | Work: <clive@demon.net>
Tel: +44 181 371 1138 | Software Development | Home: <clive@davros.org>
Fax: +44 181 371 1037 | Demon Internet Ltd. | Web: <http://www.davros.org>
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