This paper proposes a chaotic communication approach using indirect coupled synchronization scheme with high power encrypted signals. The proposed scheme is carefully designed so that the encrypted signal does not deteriorate the synchronization unlike in traditional communication methods. The synchronization problem is solved using observer-based controller. The advantages of this approach are the general and systematic feedback observer design methodology suitable for convergence rate of synchronization; flexibility in selection of chaotic signals for cryptosystem secure key generator; and improvement of the frequency-domain characteristics of the transmitted message. Computer simulations show that the synchronization between the transmitter and the receiver is more robust for different amplitude values of the information signal, even in the presence of external disturbances.