  In this paper, we develop a new cellular automata-based linear model for
several nonlinear pseudorandom number generators with practical applications in
symmetric cryptography. Such a model generates all the solutions of linear
binary difference equations as well as many of these solutions are
pseudo-random keystream sequences. In this way, a linear structure based on
cellular automata may be used to generate not only difference equation
solutions but also cryptographic sequences. The proposed model is very simple
since it is based exclusively on successive concatenations of a basic linear
automaton.
