Question

Are there any ways to encrypted a project in ASP.NET, so my customers can not change change the function where it checks the license code?

Answer 1

Take a look at Eziriz’s .NET Reactor. It’s pretty good at protection. From ther site:

.NET Reactor prevents decompilation by
a variety of methods which convert
your .NET assemblies into processes
which no existing tool can decompile (
and which are also very likely to
prevent decompilation by any future
tool). .NET Reactor builds a native
code wall between potential hackers
and your .NET assemblies by producing
a file which cannot be understood
directly as CIL. Because the CIL in
your assembly is emitted intact only
at run time or design time (in a form
in which the source is completely
inaccessible), no tool is capable of
decompiling .NET Reactor protected
assemblies.

The native code wall created by .NET
Reactor between the hacker and your
source includes industry leading
NecroBit technology, which is
exclusive to .NET Reactor. .NET
Reactor’s protection has never been
broken since the first release in
2004. These technologies make reconstruction of your source code
more difficult by so many orders of
magnitude that NecroBit is by far the
most effective protection you can use
for .NET assemblies.