There is done a lot of research into adding a non-modifiable watermark to .NET assemblies that is hard to remove again, but sadly many of these programs do not prevent recompilation of watermarked .NET DLL/EXE. Skater .NET obfuscator dev team was working on the option of adding a unremovable watermark…
Answer: How to add a watermark to a .Net DLL or EXE (to trace the copyright)?
Skater - Aug 28 '22 - 
