A method of executing a program by a processor, and an electronic entity including such a processor, the method includes the following steps: a calling program calling a subprogram and passing at least one parameter; the subprogram determining a return status indicator; the subprogram determining a return word by using a predetermined function to combine at least the return status indicator and the parameter; returning to the calling program with the determined return word as a result; and the calling program comparing the return word and a determined word determined by using the predetermined function to combine at least one possible value of the return status indicator and the parameter passed when calling the subprogram.