In this work, a transmission scheme based on the hybrid and chaotic dynamics for private communications is proposed. The transmitter is composed of a continuoustime system and a discrete-time system in which the message is inserted by inclusion. The states of the continuous system are also included, after sampling, in the discrete system. The receiver is composed of a discrete-time delay observer and a continuous-time observer. The principle of the proposed hybrid method is to show that the reconstruction of discrete states of the receiver and the message passes at first by a synchronization of the two continuous-time chaotic systems. This new strategy makes the system of transmission robust, in particular against an attack known plaintext. Simulation results are presented to highlight the performances of the proposed method.