standards...

[wcs at anchor.ho.att.com]

> > AFAIK, RSA is the only feasible PK scheme available.  There's eliptic
> > curves, of course, but that's patented.
> There are plenty of others, like Rabin's scheme, that are quite
> practical, but just not used because they are all collectively
> patented. After that patent expires in '97 things may change.

There are different uses for public-key systems, and some systems
support some but not all of the uses.  For instance,
Diffie-Hellman is useful for key exchage (and patented till 1997),
and the NIST/NSA's DSS Digital Signature Standard is useful for signatures,
especially if you like subliminal channels in your signatures :-), 
though the patent status depends on whether you believe NIST or RSA ....