A new idea of using one-dimensional PWL map in digital secure communications - Dual-resolution approach

In this brief, a new approach of using 1-D map in digital chaotic encryptio n systems is presented. This scheme utilizes a class of 1-D piecewise linea r(PWL) map with different discretization on its input and output terminals to realize finite precision chaotic encryption and decryption systems throu gh the inverse system approach. This kind of map has the property of differ ent discrete-value sets on its input and output terminals, and is called a dual-resolution map. The general structure of encryption systems that utili ze a dual-resolution map is proposed, in which a dynamical system Sigma>(*) over bar *(.) is used to connect the n-order delay line with the input ter minal of the dual-resolution map. Bn example encoder with a four-order dela y line is given to promote an understanding of the performance of this new type nonlinear digital encryption system. Simulation results shows that the zero-response of the encoder has a d-like auto-correlation function and th e response sequences converge to cyclic sequences with long period. The dec oder (inverse system of the encoder) is sensitive to all parameter mismatch es, so it can provide high security of the encrypted signals and can be use d in real-time digital secure communications when high security is needed.