In an embodiment a method includes compiling, by a processor in a compiling phase, a software program intended to be executed by the processor, the processor having secure and non-secure access right level execution contexts, and/or privileged and non-privileged access right level execution contexts and generating, in the compilation phase, instructions in machine language having an exclusively secure access right level when the instructions are intended to be executed in the secure access right level execution context, and instructions having a non-privileged access right level when the instructions are intended to be executed in the non-privileged access right level execution context.