🚀 go-pugleaf

I am currently looking into a public key encryption system for a bulletin board
network program. However, RSA is fairly CPU intensive, and the need for the
ultimate security is not great. It would be sufficient to merely be 'difficult'
for an average type. But the system really MUST be public key because any methodof passing keys makes the whole thing useless. So, is there any other function
that provides reasonable security, ie protection from casual passers-by, that
still has the RSA properties of being able to distribute a public key? This
would allow each user to generate their own key and send the public version by
ordinary mail.

-your help is appreciated-
dov