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 Robotics / RCX / legOS / 2349
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Subject: 
Re: RCX as a PGP engine
Newsgroups: 
lugnet.robotics.rcx.legos
Date: 
Sat, 9 Mar 2002 14:52:00 GMT
Viewed: 
2037 times
  
Michael J Ash wrote:
Well, maybe. Maybe not. legOS has a random() function, right?

The key word is a "good" generator. Random() is way too predictable to use
in a crypto application.

Excellent point, Benton Jackson e-mailed me with the following:

I can't reply in the Lugnet forum, because the moderators haven't
approved me yet, but I have something to add about random number
generation on the RCX for Crypto.

You need to think outside the box here. The "box" here being the RCX.
Mechanical devices can come up with very unpredictable results, and
we have lots of mechanical legos we can hook up to make a mechanical
random number generator. The first thing that comes to mind is a wheel
of fortune device, with a light sensor, a motor, and colored bricks.
We'd need to do some testing to find something that is properly
non-deterministic, though, and not just use "common sense".

Good idea using a external sensor to seed some sort of random number
generator function.  However, the codebase for PGP is pretty darned
large and after looking at the source for GPG and the international
version of PGP, I doubt you could get anything but just a small
subset of the PGP encryption engine into the RCX's limited memory.
It wasn't a serious project anyways, just a interesting proof of
concept thingy.  More power to the Uber Codewarrior who does it
though...

Part of the problem is that to even to encrypt/decrypt, you'll
need to use some pretty large number routines which look pretty
memory intensive.

Remember we are dealing with prime numbers w/ hundreds of digits.  To
generate these primes for key generation alone would be beyond our
humble RCX.  That's just for the Public Key Exchange/Encryption
portion of PGP, we haven't even implemented the Symmetrical Cypher
part.  I think this latter part could be implemented easily (though
it would run a bit on the slow side :) on the RCX however.

I figure that you'd likely want to import your existing PGP key
(that you've already generated on your PC/Mac/Mainframe/Cray/etc)
to use on your RCX Decodomatic anyways.

Oh well, it was a funny idea though.  I might tackle getting a simple
symmetrical encryption engine put onto the RCX like IDEA or Blowfish
as a first step some day.  The performance/memory issue does keep
rearing it's ugly head though, may have to think about coding in
Native RCX Assembler to get the job done... :)

Dave

--

dcchen <at> pacbell <dot> net



Message has 1 Reply:
  Re: RCX as a PGP engine
 
(...) It really isn't that limited when you consider other platforms that run full PK systems, such as the Dallas Semiconductor iButton. It has a much more limited processors, more limited RAM, and you write your code in Java so it has to be (...) (22 years ago, 9-Mar-02, to lugnet.robotics.rcx.legos)

Message is in Reply To:
  Re: RCX as a PGP engine
 
(...) The key word is a "good" generator. Random() is way too predictable to use in a crypto application. (22 years ago, 9-Mar-02, to lugnet.robotics.rcx.legos)

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