For Java there's License4J: http://www.license4j.com/ http://www.license4j.com/ There should be similar tools for other languages as well. My suggestion is to

For Java there's License4J: http://www.license4j.com/ http://www.license4j.com/ There should be similar tools for other languages as well. My suggestion is to not overthink it. There's no perfect solution that will prevent your software from being copied in every scenario imaginable. Just use common sense. It certainly shouldn't take 2 months to implement. Your customers aren't paying for copy protection after all.