Fuzzy Observer Design with n-shift Multiple Key for Cryptography Based on 3D Hyperchaotic Oscillator

A fuzzy observer based scheme for synchronizing two hyperchaotic oscillators via a scalar transmitted signal for cryptographic application is proposed. The Takagi-Sugeno fuzzy model exactly represents chaotic systems. Based on the general fuzzy model, the fuzzy observer of a chaotic system is designed on the basis of the n-shift multiple state based key encryption algorithm. The scalar transmitted signal is designed in such a way that the hyperchaotic carrier masks the encrypted signal, which in turn hides the message signal. Simulation results show that the proposed scheme gives a better performance even when a small additive stochastic noise is present in the channel.