  Commutativity of subsystems in cascade connected forms to form larger systems
gets worthy to improve noise disturbance properties, stability, robustness and
many other properties in system design. In this paper, another benefit of
commutativity property is indicated, as far as the author knowledge for the
first time, and illustrated by examples. This benefit is the gain of a new and
original method for transmission of secret signals when travelling in a
transmission channel. Hence, the paper presents an original and alternative
method in cryptology. Their results are all validated by illustrative examples
and Matlab simulation toolbox Simulink.
