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CRYPT

3 expanded posts ยท every known parent and child

NODE 63a0545cCRYPT
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.

Ryan Snyder, Consultant  | --->Finger me for my PGP public key.<---     ___ 
University of Montana CIS|                                             |\ /|
CS000RRS@SELWAY.UMT.EDU  |     Copyright 1994 by Ryan R. Snyder.       | 0 |
RYE@ILLUMINATI.IO.COM    |                                             |/_\|
RYE@CYBERSPACE.ORG       |
NODE 3243fe69CRYPT
>I am trying to crack a textfile which has been encrypted with a program 
>(for the IBM) called CRYPT. 

The first thing you want to know is what the underlying algorithm used
was.  The documentation might tell you.  The source code would tell
you.  Disassembled object code would also tell you.

Do you have any of these?

Eric
NODE 4837dccaRe: CRYPT
> 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