As far as I know, there's no way around this, if someone is intent on stealing your source code, and say you have it encoded, which can be done free online using tools already available, there's always a way to decode it.
If you're using a programming language, say PHP for example, it gets parsed into HTML, which is all someone viewing your source would see, therefore it's harder to steal as they'd have to program it themselves and don't have access to your actual scripts because they get parsed by the server.
Hope I explained that right and that it helps.