This work describes a novel scheme that applies a Sprott master/slave chaotic synchronization system to secure transmission. A sliding plane is chosen to design a sliding mode controller to ensure robustness. In the presence of an external disturbance and system uncertainty, the slave chaotic circuit system is then synchronized with the master. The Lyapunov theorem verifies that the proposed controller is stable and robust. Simulation results indicate that the synchronization error state asymptotically converges to the origin of the phase plane, implying that the master/slave chaotic system synchronization is achieved while the sliding mode controller is in operation. While consisting of operational amplifiers, resistors, capacitors and diodes, the chaotic circuit system together with a sliding mode controller is subsequently implemented to validate the system synchronization. Finally, the chaotic system combined with cryptography is embedded into a chaotic synchronization cryptosystem to resolve secure communications-related problems.