Chaos encryption method based on large signal modulation in additive nonlinear discrete-time systems
Victor Grigoraş, Carmen Grigoraş · 2006
Abstract:- The present contribution deals with digital data encryption by means of discrete-time chaos synchronization. By this combination of analog nonlinear dynamics with digital signal processing, a larger number of encryption keys and higher computational complexity to break the code is expected compared to standard digital encryption techniques. The chaos synchronization system is based on an emitter structure similar to that of a recursive digital filter with single, piece-wise linear, periodic type nonlinearity. The use of additive nonlinearities simplifies the design of the system, allowing easy calculation of the emitter Lyapounov exponents and straightforward, inverse system design of the synchronizing receiver. Moreover, the problem of noise sensitivity, present in analog chaos synchronization setups, is totally removed by using channel quantization. The large modulating signal approach, combined with large maximum Lyapounov exponent of the emitter and use of an output bit shuffling circuit, helps cover some of the previously noticed drawbacks of the chaotic approach to digital signal encryption. Key-Words:- chaos encryption, chaos synchronization, additive nonlinear discrete-time systems