Polytopic observers for the estimation of time-varying delays of discrete-time polynomial chaotic systems

A cryptosystem based on polynomial chaotic discrete-time delayed systems is presented in this paper. It consists in injecting an information as delay into a chaotic system. The outcome of such an approach is to increase the dimension of the system and therefore to increase the security of transmissions. The main point is the design of a suitable receiver achieving the deciphering which cannot be performed as in the continuous-time case. As a clue to tackle the problem, the deciphering is reformulated as polytopic observers design problem for LPV polytopic systems.