This paper considers interactions between cellular automata and cryptology. It is known that non-linear elementary rule which is correlation-immune don't exist. This results limits the use of cellular automata as pseudo-random generators suitable for cryptographic applications. In addition, for this kind of pseudo-random generators, a successful cryptanalysis was proposed by Meier and Staffelbach. However, other ways to design cellular automata capable to generate good pseudo-random sequences remain and will be discussed in the end of this article.