In this paper, a modified robust adaptive chaos synchronization structure is proposed. To increasing the security of the communication network the parameters of the chaotic transmitter is changed. By changing the parameters of the chaotic transmitter (sender section) the conventional state observer (receiver section) cannot be retrieved the actual states properly and the performance of state estimation will be corrupted. By adding on-line parameter identification subsystem to receiver section the performance of the overall system will be improved noticeably. The simulation results exhibit high efficiency of the proposed scheme.