  A Cellular Automata (CA) is a computing model of complex System using simple
rule. In CA the problem space into number of cell and each cell can be one or
several final state. Cells are affected by neighbours' to the simple rule.
Cellular Automata are highly parallel and discrete dynamical systems, whose
behaviour is completely specified in terms of a local relation. This paper
deals with the Cellular Automata (CA) in cryptography for a class of Block
Ciphers through a new block encryption algorithm based on Reversible
Programmable Cellular Automata Theory. The proposed algorithm belongs to the
class of symmetric key systems.
