Basic Public key algorithms.

[droelke@rdxsunhost.aud.alcatel.com (Daniel R. Oelke)]

After doing quite a bit of poking around, I am somewhat discouraged
in my attempts to find a simple *pure* public key encryption method,
without a lot of other stuff wrapped around it. 

What I need is to encrypt between 45 and 55 bits of information
using a public key algorithm in an embedded environment. 
Memory usage needs to be minimal (a couple of K), and CPU usage 
will be tradded off based on key length.  Decryption speed/memory 
usage is not very limited (done on a workstation, not on embedded
system).

I could use RSA (which is well described in many sources, and has
RSAREF out there),  but I want to avoid the patent issue if possible.  
The sci.crypt FAQ mentions that there are other methods but that 
is about all it says.  Are there any that are not patented?  Are there
any that someone knows of that work well in a limited memory
environment? 

Thanks for any/all pointers.

Dan
------------------------------------------------------------------
Dan Oelke                                  Alcatel Network Systems
droelke@aud.alcatel.com                             Richardson, TX