  A wide family of nonlinear sequence generators, the so-called
clock-controlled shrinking generators, has been analyzed and identified with a
subset of linear cellular automata. The algorithm that converts the given
generator into a linear model based on automata is very simple and can be
applied in a range of practical interest. Due to the linearity of these
automata as well as the characteristics of this class of generators, a
cryptanalytic approach can be proposed. Linear cellular structures easily model
keystream generators with application in stream cipher cryptography.
