An Application of Non-Uniform Cellular Automata
for Ecient Cryptography
A. Kumaravel
1*
and Oinam Nickson Meetei
2
1
Dean & Professor,
Department of Computer Science & Engineering
Bharath University, Chennai; drkumaravel@gmail.com
2
PG Scholar, Department of Computer Science & Engineering
Bharath University, Chennai; nickson_s@hotmail.com
Abstract
One of the core issues for robust cryptographic systems is to deal with the rate of diusion and distribution of keys. We try
to strengthen this aspect by increasing the length of block ciphers. We present a new encryption and decryption algorithm
for block cipher that supports 2
7
bit block size. All components in our system are chosen to be based on cellular automata
so as to achieve higher parallelism and to simplify the in hardware and software implementation for applications with high
degree of security. The main objective of this paper is to increase the complexity by novel schemes of mixing (reversible
cellular automata) RCA and (non-uniform reversible cellular automata) NRCA. We apply set of dierent bit permutation
methods for this purpose .This paper establishes the proof for existence of yet another approach for a high quality pseudo-
random bit sequences generated by non uniform cellular automata.
Keywords: Cryptographic System, NRCA-non Reversible CA, Pseudorandom Number, RCA-Reversible Cellular
Automata.
1. Introduction
Two main cryptography systems are used today: symmetric
systems (aka secret key systems) and public-key systems.
An extensive overview of currently known or emerging
cryptography techniques used in both type of systems can
be found in [1, 9]. One of such a promising cryptography
technique is applying cellular automata (CAs).
e main concern of this paper is secret key systems.
In such systems the encryption key and the decryption key
are same (symmetric key). e encryption process is based
on generation of pseudorandom bit sequences, and CAs
can be eectively used for this purpose. Cellular Automata
(CA) is an organized lattice of cells and each cell have nite
number of states, such as “TRUE” (T) or “FALSE” (F). e
lattice dimensions can be of any nite value. Each cell within
a collection of cells is called as hood. It is characterized
relatively with respect to a particular cell. To start with at
time t=0, a state is assigned to the cells. e new states of
the cell depend on its own previous state and states of its
neighborhood. e new states are assigned based on some
predened rule using mathematical calculations.
Encryption, by theory requires highly complex actions
such as permuting, ipping and altering data in such a way
that it is undecipherable and provides complex relationship
with the original text and the keys. is relationship should
be non-linear so that decryption is as tough as possible. e
encryption process must be faster in time and cheaper in
terms of the components involved [2, 7]. CA provides a basic
structure for highly parallel and complex operations upon
which a basic encryption scheme can be built. e message
encryption is done by Pseudo Random Number Generators
(PRNGs) using CA. e generation of new states in One-
Dimensional (1-D) CA, can be considered as a sequence of
* Corresponding author:
A. Kumaravel (drkumaravel@gmail.com)
Indian Journal of Science and Technology
Supplementary Article