I really do not want to go to Java or Python, but for this project to work some modules must be delivered without the raw source.
Why would Java or Python be more secure? Don't they face the same fundamental problems? (Googling for Java Decompiler is instructive).
This sort of question has been asked here many times:
Concealing Perl Code
simple encryption for perl files
Protect source code
Perl Obsfucate Or Encrypter
Closing Perl Source
Here is a commercial obfuscator
perl2exe - no more secrets
Protecting perl source code
Why is it bad to hide the source?