This is true: every software developer knows (or should know) that you can compile a C program with backdoors, and hide the traces (using a special compiler). Every OS out their is still written in C, despite much better languages available, and incredibly powerful systems existing in the past, like Lisp Machines, which had absolutely no technical problems, were far superior, but somehow never took off (for no logical reason really, although many IT "experts" will explain everything away, but non convincingly). And let's not even start to talk about backdoors in processors...