From: Mike Duvos <enoch@zipcon.net>
Date: Sat, 23 Aug 1997 05:48:08 +0800
To: cypherpunks@cyberpass.net
Subject: Re: Mathematics > NSA + GCHQ
In-Reply-To: <1.5.4.32.19970822193215.00831fc0@pop.pipeline.com>
Message-ID: <19970822212925.30178.qmail@zipcon.net>
MIME-Version: 1.0
Content-Type: text/plain



John Young writes:

> Along this line:

> A few days ago we received an 8-page excerpt from "Shift Register
> Sequences," by Solomon W. Golomb (at USC), Holden-Day, Inc., 
> no date, with a handwritten note:

>    NSA has tried to suppress knowledge of this stuff. Nearly all NSA 'good'
>    algorithms are based on this technology.

> IANAM, so would any of the mathematicians here give any credibility to 
> this claim?

"The Magic Singing and Dancing Shift Register Algorithm" has been making
the rounds for a number of years now, and surfaces in various forms at
periodic intervals on the Net. 

It is based on a mathematical technique once used to do transcendental
function approximation on now slow and obsolete calculator chips, and as
far as I can tell, offers no magic insights into efficient ways of
computing cryptographically interesting functions, such as factoring,
descrete log, or symmetric block cipher key recovery.

I would put it in my comedy file along with the "RSA is Easy To Break"
paper, and similarly innumerate rants. 

> We'll scan and put the excerpt on our Web site if worthwhile.
> It's composed of the book's 3 page preface and 5 pages of text and
> diagrams of Chapter 2 on The Shift Register as a Finite State Machine,
> with principal focus on de Bruijn diagrams for shift registers.

The book is probably a serious text on the mathematical techniques in
question.  But unless you are looking for a way to compute Trig functions
with lots of iterations and little hardware, it probably isn't worth more
than a cursory glance.  It's not going to break codes for you.

--
     Mike Duvos         $    PGP 2.6 Public Key available     $
     enoch@zipcon.com   $    via Finger                       $
         {Free Cypherpunk Political Prisoner Jim Bell}