A new approach for secure communication using constrained hyperchaotic systems

In this paper, a new technique is developed for a typical secure communication scheme. In this approach, we introduce the concept of constrained hyperchaotic systems to encrypt the carrier of the data signal to be transmitted. At the transmitter end, two different chaotic oscillators are coupled, constrained and used as a new hyperchaotic system. One of the outputs of the constrained hyperchaotic system is used as a carrier for the encrypted data. Then, the outputs of the system, including the modulated carrier, are encrypted using a set of pre-defined encryption rules. At the receiving end, and after decrypting the received outputs, the discrete-time Constrained Regularized Least Square (CRLS) estimator is used to reconstruct the constrained hyperchaotic signals, and hence retrieve the transmitted data. Simulation results are presented to illustrate the capability of the CRLS estimator in reconstructing the states of the constrained hyperchaotic system. Moreover, the proposed secure communication scheme is applied to transmit discrete images for which the quality of the transmission process is measured by the bit-error rate (BER).