From: Jim Gillogly <jim@rand.org>
Date: Tue, 5 Apr 94 12:49:33 PDT
To: cypherpunks@toad.com
Subject: Re: CRYPT
In-Reply-To: <Pine.3.89.9404051333.D1183-0100000@selway.umt.edu>
Message-ID: <9404051949.AA03223@mycroft.rand.org>
MIME-Version: 1.0
Content-Type: text/plain



> Ryan Snyder--Consultant <cs000rrs@selway.umt.edu> writes:
> I am trying to crack a textfile which has been encrypted with a program 
> (for the IBM) called CRYPT. Can anyone help me with a method, a program 
> which will break it, or a pointer to more information on how I might go 
> about it? Thanks in advance.

If that's the program I wrote back in '82 called CRYPT and marketed
through the Software Toolworks and Norell Data Systems, then you should be
able to break it with crib dragging, if you know enough plaintext.  It
XORed the output of a linear feedback shift register against the text.
The documentation listed that attack under "bugs".  Depending on how you
select keys, it might be easier to brute force it against a dictionary.

If that's not the program, try giving more identification on it...

	Jim Gillogly
	Highday, 14 Astron S.R. 1994, 19:48