Chaotic secure digital communication scheme using auxiliary systems

In this paper, we present a new secure message transmission scheme using hyperchaotic discrete primary and auxiliary chaotic systems. The novelty lies on the use of auxiliary chaotic systems for the encryption purposes. We have used the modified Henon hyperchaotic discrete-time system. The use of the auxiliary system allows generating the same keystream in the transmitter and receiver side and the initial conditions in the auxiliary systems combined with other transmitter parameters suffice the role of the key. The use of auxiliary systems will mean that the information of keystream used in the encryption function will not be present on the transmitted signal available to the intruders, hence the reconstructing of the keystream will not be possible. The encrypted message is added on to the dynamics of the transmitter using inclusion technique and the dynamical left inversion technique is employed to retrieve the unknown message. The simulation results confirm the robustness of the method used and some comments are made about the key space from the cryptographic viewpoint.