An improved chaotic shift keying technique

In this paper, an improved technique for constructing chaotic shift keying for transmitting digital signals is introduced. The key idea is allowing the chaotic transmitted signal to alternate between four different chaotic attractors, in contrast to the classical methods where only two chaotic attractors, representing logic 0 and logic 1 are used. This has the effect of effectively hiding the secret message and providing better security and privacy against intruders´ attacks to the public communication channel. A Duffing oscillator is used to build the proposed system, where synchronization of both the transmitter and the receiver is carried out using a Lyapunov-based control approach. At the transmitter side, the parameters are used to encrypt the secret message using a novel XOR-based digital function. At the receiver side, synchronization is achieved using a parameter update law to decrypt the transmitted signal. Tuning the control parameters is discussed and suggestions regarding improving the performance are provided.