On Mon, 6 Sep 1999, Arnold Reinhold wrote:

> If a field worker might have access to  a computer in country but 
> would not be in a position to use PGP, I'd suggest CipherSaber, which 
> is based on RC4 and is simple enough to program from memory (see 
> http://ciphersaber.gurus.com). Almost all PCs come with Qbasic built 
> in or on the CD-ROM. I haven't tried it, but CipherSaber should fit 
> easily into most of the newer graphing calculators (The $200 TI-92+ 
> even has a qwerty keyboard. See http://www.ti.com/calc).

Yeah, I have no doubt that RC4 could be implemented quite easily on
TI calculators (certainly on the 85, 86, 92 and 89 .. and probably
on the 82 and 83 as well .. though I haven't programmed them). 

I did MD5 on my 92 awhile back. 

A couple of points in making an actual crypto application on the TI
(as opposed to just doing an algorithm):

   Transferring ciphertext from the TI to a computer would require
   a utility on the computer to wrap up the ciphertext to make it look
   like a list to the TI. Then the TI can do nice, easy subscripting
   to access the list. A table might be needed to display the plaintext,
   since I don't know if they use ASCII. 

   On the 89 and 92, things will be easier. They use ASCII, and have
   lots of nice internal display features to do paging and stuff. 

   Unfortunately, I've found documentation on the internal data formats to
   be a bit lacking. I wrote utilities awhile back to convert to/from TI
   92 bitmaps to UNIX raw PBM's.. I found dox on the graphics format
   which work, but don't include info on how the supposed-checksum is
   performed (not that having it wrong makes a difference).. and the
   text-file description that I found is all wrong.. so writing a utility
   to convert the ciphertext to a list might be problematic. 

Michael J. Graffam ([EMAIL PROTECTED])
"Our merchants and master-manufacturers complain much of the bad effects
of high wages in raising the price, and thereby lessening the sale of
their goods both at home and abroad.  They say nothing concerning the bad
effects of high profits.  They are silent with regard to the pernicious
effects of their own gains." - Adam Smith, Wealth of Nations, Book I Chap. IX.

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