Concealing-Restoring System for Physical Layer Data Based on Stochastic Filtering Theory

We propose a concealing-restoring system (CRS) for data on physical layer of the OSI reference model. CRS conceals those data by disturbing them with some random noises, and restores the data from the concealed ones to the original ones by using the noise elimination based on a proper stochastic filtering theory. Although we introduced the outline of the almost linear version of CRS in our previous work [Fujii & Hirokawa, Math. Industry, Springer (2020)], we explain its details, and study its nonlinearization to improve the security of CRS in this paper.