public /private key to post message in the forum

Can we use public key encryption to post a message in the forums?

I think the forum software has to support such a feature first !

Granted the forum software would ideally need to support it, you could just cut and paste a message that has been encrypted with the public key. That said, it'd be limited to a single person with the corresponding private key, so it'd be rather useless and a waste of space. Would make more sense to send that person an email or PM with it encrypted using their public key.