A. Synthesis and Linearization of Nonlinear Feedback Shift Registers -basis of a Model of Memoryt Linear Shift Registers Have Been Extensively Studied since the Pioneering Work Of

Linear shift registers have been extensively studied since the pioneering work of D. A. Huffman. A general theory was created by Huffman, l Golomb, Elspas, Stern, Friedland, Zierler, Hartmannis, Massey, and others. This progress was mainly due to the identification of the operations performed by linear switching circuits with algebraic operations over Galois fields. There was no general theory for nonlinear shift registers, however.