Part 2 Approaching .net protection by decompile/modify/compile
Run 'ildasm' and open a .net assembly, you will see how the file is broken down to variables, methods, resources, etc. You can dump the assembly to a text file containing CLR intermediate language. Once you have the text file, you can start making changes to the IL. Afterwards, run 'ilasm' on the dumped/modified assembly text file and resource files to generate a modified binary, either a DLL file (use '/DLL' flag with ilasm) or a EXE file. Resources can be included with /RESOURCE= flag.
Simply modify IL will generate CLR load file exception. This is due to .net strong name security check. Inside the .net IL text file, usually at the begining, you can see that it has a public key and a hash code used by the strong name security scheme. To bypass strong name check, remove these key related text and recompile. This will do the trick.