C#: How to Make it Harder for Hacker/Cracker to Get Around or Bypass the Licensing Check? [closed]

Solution 1:

The #1 law of software licensing: You don't control your software once you allow it to be installed on a computer you don't control.

If you want to keep control over your code, you need to make it a web service and give the end user just a thin client that interfaces to that web service.

In many scenarios, this is unacceptable, because users want to be able to use their software even when they don't have an internet connection.

In almost all cases, you should focus on making the user experience better, and all forms of copy protection make it worse instead. Once you get to the point where the experience of downloading from a warez site and running it through several virus scans is better than doing the license setup for the legit version, you've lost.

Solution 2:

You can obfuscate the code (make it harder to decompile/use the reflector on it), but with enough energy and knowledge, it will get broken, after that it's quite easy to change the bytecode of the assembly, thus circumventing the license check. Also, you could invest the money to make it possible for you to sign your assemblies, which would make it harder to change the assembly itself, but with enough energy (more than just breaking the obfuscation) this can also be circumvented.

Your goal shouldn't be to make the license process unbreakable, but to make your software itself worth to buy. This is a much better protection. Crackers (and only them, hackers are something completely different, see this article for more) won't be hindered by that, but with the software being worth it, much more people would buy it.