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[MachineForth] [Nosc] 25x Forth engine

--- Andy Valencia <vandys@xxxxxxxxx> wrote:
> This is where it gets critical.  If you look at
> Cisco's "Toaster" network
> processor

This all reminds me of the Switcherland project.


This project builds a "desk area network"
using switched nodes as opposed to busses.
The idea is similair to ATM and in fact some
have built "desk area networks" using ATM
switches, but due to being optimized for 
relatively small networks Switcherland is
much faster.  Switcherland is implemented
using FPGAs but I could see much of the 
functionality being handled by a 25X.

> I've spent a fair bit of time trying to sketch out a
> DES key search

As some have pointed out, DES might not be the
best app for a 25X, but not for the reasons that
they gave.  While DES can make use of special 
hardware, it was first implemented on an IBM
mainframe, and most of the time today DES is
used via standard hardware such as Pentiums and
PowerPCs.  It's moderately fast as far as
encryption algorithms go.  (The SWIFT banking
standard uses RSA to pass a DES key and DES to
encode the data stream because DES is much faster
than RSA on most hardware). I've implemented DES 
in Fifth and Win32Forth.  The basic instructions 
are within the machine forth instruction set.  
(XOR, shift, AND ect.)  The problem is that DES is
inherently a 32/64 bit algorithm.  Implementing
that on a 18 or 21 bit machine would be difficult
IMHO.  The IDEA algorithm used in PGP is also
wordsize dependent, though it may be easier to
work around than DES because the algorithm is
simpler.  You could certainly use encryption 
algorithms that don't have wordsize dependencies
such as the solitaire algorithm:


However if you were using a 25X as a web server
you would be pretty much stuck with using an
algorithm that was used by the browsers and
other servers you were communicating with.

Another interesting question is how fast could
one get RSA to run on a 25X?  There's no wordsize
dependency here, but it does require heavy use
of multiplication and division which are not
strong points of the X18.  But perhaps there is
an algorithmic way around this.

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