Path: utzoo!utgpu!news-server.csri.toronto.edu!cs.utexas.edu!uunet!tron!rtaylor
From: rtaylor@tron.UUCP (Randy Taylor)
Newsgroups: comp.os.msdos.misc
Subject: Re: File protection in MS-DOS
Message-ID: <682@tron.UUCP>
Date: 15 Dec 90 20:22:53 GMT
References: <3920@male.EBay.Sun.COM> <51060001@hpcupt1.cup.hp.com> <5034@bwdls58.UUCP>
Reply-To: rtaylor@tron.bwi.wec.com.UMD.EDU (Randy Taylor)
Organization: Westinghouse Electric Corporation
Lines: 62

In article <5034@bwdls58.UUCP> mlord@bwdls58.bnr.ca (Mark Lord) writes:
>In article <51060001@hpcupt1.cup.hp.com> swh@hpcupt1.cup.hp.com (Steve Harrold) writes:
><>>> To repeat: ANY SECURITY SYSTEM WHICH DOES NOT HAVE A PHYSICAL DEVICE
><>>> UNDER PHYSICAL PROTECTION CANNOT PROVIDE REAL SECURITY. 
><>>> --- Tom Roberts
><----------
><How would you classify schemes such as DES or the public key encryption
><schemes.  Surely, given enough time they can be decoded, and by such time
><it is assumed that the data is no longer useful.  But, given enough time
><one can also remove the physical device without damage to the data.
>
>Err.. my understanding of the current DES is that it can actually be "broken"
>very quickly on existing FAST computers, owned by say, the US gvt.
>-- 
> ___Mark S. Lord__________________________________________
>| ..uunet!bnrgate!mlord%bmerh724 | Climb Free Or Die (NH) |
>| MLORD@BNR.CA   Ottawa, Ontario | Personal views only.   |
>|________________________________|________________________|

Hi all !

There is a PC-employable algorithm for data encryption called MPJ.
I picked up info on this from CompuServe in the IBMSYS forum. There
is a Master's Thesis called THESIS.DOC and a ZIP file with a menu-driven
program that uses the MPJ routine on the file you specify.

MPJ goes beyond DES (apparently WAY BEYOND). The key is a series of 16 
individual hex digits ranging from 00 to FF. According to the thesis, it
would take a string of supercomputers 10,000+ years to break the encoded
data. I did some rough calculations and figured that, with the available
number of keys and a computer running at 1 picosecond per key try, it
would take about 1 x 10^19 years to break the code ! :-()

The problems with MPJ (in my opinion) are :

1) Remembering the key. There are 256^16 of them, which is good, but each is
   16 digits wide, which is bad on the brain ! 

2) It is in the public domain which means the guys at the "Puzzle Palace", 
   (just down the road from where I work) are busily working on cracking it,
   if they haven't already done so. DES was "tamed" somewhat by this same 
   group so that they could get the encoded data no matter what and we 
   couldn't (unless we had the key). 

The thesis has the source code (in Turbo Pascal) included. I wish I could
remember the name of the author so I could properly credit him, but it
escapes me. 


Randy Taylor
Westinghouse Electric Corp.
Electronic Systems Group

PS - Please e-mail comments or questions to the addresses listed below. I
     don't make it to this forum very often. Thanks :-) !

RT
-- 
rtaylor@sky00.bwi.wec.com  from an Internet site (preferred) 
rtaylor@tron.bwi.wec.com   from an Internet site (alternate)

"...you know I have the greatest enthusiam for the mission." HAL 9000