Secure communication application with chaotic systems

Chaotic systems are nonlinear dynamical systems and the most important features of the chaotic systems are sensivity on initial conditions, having nonperiodic behavior and noise like wideband spread spectrum. Several control mechanisms and algorithms have been developed to control the unwanted chaotic behavior of the systems and to prevent the chaotic behavior of the systems. On the other hand, the positive aspects of the chaotic systems are used in many areas like biomedical and medical applications, random enumerators, encryption, secure communication. The chaotic systems and noise have similar wideband spread spectrum. This similarity allows the transmission of the information signal in a secure way. In secure communications literature, the researchers generally use Chua, Lorenz, and Rössler systems and implement the chaotic systems using OP-AMP. In this thesis, chaotic circuits of Sprott A, Sprott B, Sprott G, Sprott H, and Diffusionless Lorenz systems and communications circuits of Sprott A, Sprott B, and Diffusionless Lorenz systems are designed. All circuits are designed using OTRA, CCII, and CCIII instead of OP-AMP and they are never used as a functional element in the chaotic systems. Since current mode circuits have larger bandwith, higher exchange rate, wider dinamic range, lower power consuption, simpler circuit structures and larger linearity field like characteristics than voltage mode circuits, all circuits are designed with OTRA, CCII and CCIII for the first time. Key Words Chaotic Systems, Secure Communication, Functional Elements, OP-AMP, OTRA, CCII, CCIII