On the decomposition of an NFSR into the cascade connection of an NFSR into an LFSR

In this paper, we study the decomposition of an NFSR into a cascade connection of an NFSR into an LFSR which is a kind of concatenation of an NFSR and an LFSR. It is shown that this problem can be solved based on polynomial factorization in F2[x], and a potential weakness of an NFSR that can be decomposed in such a way is further discussed.