Protecting Your Code/DLL's

Hello, I am interested in finding a more secure way of protecting our code and dll's we have made to be used with Nx. The trouble is that you need access to the files(unless there's another way) to be able to run them within Nx. I've thought about obfuscating the code but that just slows the hacker down essentially. While it might deter most people from stealing the code, I am still on the search for a more viable solution. If you have any ideas and can point me in the proper direction, it would be very appreciated.