This paper presents a symmetric key block cipher technique using Cellular Automata (CA). The proposed system deals with theory and application of cellular automaton. Cellular automata have the property of state transition that is basis to define fundamental transformations for encryption and decryption in the enciphering system. Firstly, the patterns are generated using MATLAB (v2011) and then the cryptographic system is implemented in C language but it can be implemented in other languages too. Different rule configurations of CA are used to form hybrid reversible cellular automata to be used in encryption and decryption of the data in the form of string or character array.

Pattern generation and symmetric key block ciphering using cellular automata

Cellular automata are discrete dynamical systems which are practical to use for simulations. Higher order cellular automata are a natural extension of cellular automata, and are expected to be a useful way of improving already existing cellular automata models. We present here an introduction to cellular automata including background, definition and notation. We then present higher order cellular automata, motivated by the notion of hyperstructures. Two examples of how higher order cellular automata are used in modelling then follows. The first model use higher order cellular automata to improve traffic flow in a graph-traffic problem derived from a set of single lane-traffic cellular automata rules. The second model shows another way of using higher order cellular automata. It is based on the majority vote cellular automaton which does a naive emulation of a voting situation in a population. Inspired by hyperstructures in a real population, higher order layers are added, and their effects on the system are observed to be significant.

A Study of higher order Cellular Automata with Examples

This thesis will give an introduction to the concepts of cellular automata and higher order cellular automata, and go through several examples of both. Cellular automata are discrete systems of cells in an n-dimensional grid. The cells interact with each other through the use of a rule depending only on local characteristics, which lead to some global behaviour. Higher order cellular automata are hierarchical structures of cellular automata with added possibilities for dynamic local interaction. We first give an introduction for non-mathematicians. A mathematical definition of cellular automata follows, and we illustrate the many possibilities with a few examples. Higher order cellular automata are introduced and defined, and we look at the consequences higher order cellular automata has on optimization of computer implementations. Finally we apply higher order structures to some of the examples, and study the effects.

Lauritz Vesteraas Thaulow

Papers

A Study and Comparison of First and Second Order Cellular Automata with Examples