Can I protect an application without touching its source code?

Yes you can, but it is not necessarily in your best interest.
Our tool, “is just a tool”.  You can use it in many different ways.

Not touching the source code is desirable when protecting legacy code with limited effort.  An example of a primitive which wouldn’t require source code knowledge is to simply run a watchdog thread doing checks for unexpected modifications and traces of being debugged.  You don’t have to program such a thread, it is a ‘primitive” included by the protection tool.

The opposite, a complex, involved protection is desirable for high level protection of critical infrastructure.

By the way:  An engineer can add markers into the source code, but that does not imply that the tool will access source code directly.  It detects the markers in compiled code (Patent pending).

In addition to using markers, it is also possible to denote ranges in the application code by using function names.