In order to improve the security of secure communication systems based on chaos synchronization, a new four dimensional hyperchaos system was built by adding an additional state into the three order Lü system. Some of its basic dynamical properties were studied briefly, such as the feature of equilibrium, the bifurcation diagram, the hyperchaos attractor, Lyapunov exponent and fractal dimension.An electronic circuit was designed to realize the four dimensional hyperchaos system. A method of chaos synchronization between the four dimensional hyperchaos system and its duplicate system using linear feedback control was proposed. Based on the Lyapunov stability theory, the range of feedback gain was derived.Computer simulation showed that the hyperchaos system has variety of states and chaos synchronization can be realized using linear feedback control.
