This may be a naive question. If it is, I'm fine with just a link to outside information. I studied RSA encryption about 2 years ago, but that's about it.

I'm just wondering: is it a matter of engineering or is it a fundamental problem? By the latter, I mean "will we always be forced to release information which could undermine secure communication?" 

This question is posed under the assumption that it is hard to achieve. Is it?