in reply to Code Encryption .. How to ??

Check the Perl faq, part 3. There is question about how to compile programs

I recently looked at this myself, since I'm writing a hobby program implementing copyrighted information that I can't release.

The publisher gave the ok for public release to hobby programs in easily decompiled Java bytecode, so I am not too worried. (I could make it a web-only program.)

If you are more paranoid, check writing a C module.