There are two huge problems that no obfuscation can address well - B::Deparse and the debugger.If your program is executable at all, B::Deparse will print the source. Similarly, if the program's executable at all, the debugger's list command will display the source code.
One of the few ways to protect your source is to host it one place and supply a thin-client front end that connects to the hosted code to perform functions. You never distribute the protected code at all.
What's the reason you want to do this? Maybe there's a better option. | 
