[1160] in cryptography@c2.net mail archive
Re: Better DES challenge update
daemon@ATHENA.MIT.EDU (Bill Frantz)
Thu Jul 3 09:41:02 1997
In-Reply-To: <199707030021.UAA08713@raptor.research.att.com>
Date: Wed, 2 Jul 1997 22:45:41 -0700
To: Steven Bellovin <smb@research.att.com>, die@die.com
From: Bill Frantz <frantz@netcom.com>
Cc: andreas@artcom.de (Andreas Bogk), eli@gs160.sp.cs.cmu.edu,
cryptography@c2.net, crisp@netcom.com
At 5:21 PM -0700 7/2/97, Steven Bellovin wrote:
>The former, by David Wagner and myself, describes a programmable plaintext
>recognizer designed to fit on-chip with a Wiener engine. The latter, by
>me, analyzes IPSEC for probable plaintext. The hardware feature you want
>for the latter is a "population count under mask" -- you XOR the target
>word with the trial decryption, then count how many 0 bits are in selected
>positions...
And now you know why machines designed by Cray have an instruction which
counts the number of 1 bits in a register (in one machine cycle).
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