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 encryption systems is presented. This scheme utilizes a class of 1-D piecewise linear (PWL) map with different discretization on its input and output terminals to realize finite-precision chaotic encryption and decryption systems through the inverse system approach. This kind of map has the property of different discrete-value sets on its input and output terminals, and is called a dual-resolution map. The general structure of encryption systems that utilize a dual-resolution map is proposed, in which a dynamical system [Sigma]([multiplied by]) is used to connect the n-order delay line with the input terminal of the dual-resolution map. An example encoder with a four-order delay 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 the response sequences converge to cyclic sequences with long period. The decoder (inverse system of the encoder) is sensitive to all parameter mismatches, so it can provide high security of the encrypted signals and can be used in real-time digital secure communications when high security is needed. Index Terms--Digital chaotic encryption, discretization, dual-resolution map.