REVIEW

Dynamic Key Matrix of Hill Cipher Using Genetic Algorithm

ABSTRACT:

This is a

technique in which we make the implementation of Hill cipher easy by using

genetic algorithm. In Hill cipher a matrix is designed to perform encryption

and decryption. We insert some integer number in the rows and columns of this

matrix. The wrong determinant result of this matrix

cannot be used in the process because while decryption it produces an incorrect

plain text. Genetic algorithms has the optimized way to finding the key which

is used for encryption and decryption on the Hill Cipher Algorithm. By implementing

this algorithm the searching of the key in Hill Cipher will be easily done in a

short time. Genetic Algorithm perform more efficient if it is combined with

Hill cipher.

INTRODUCTION:

Hill cipher

is an arithmetic technique in cryptography that is why it uses a symmetric key

to convert plain text into cipher text. Symmetric key is a system that has the

same kind of keys in encryption and decryption. But we must have to inverse the

key before decrypting a cipher text into plain text. The major part in a matrix

that is used in Hill cipher is the multiplication between the matrix and the

inverse of a matrix. Now we will know about the genetic algorithm that what is

genetic algorithm and how it works. Genetic Algorithm is a computational

algorithm and basically this algorithm is built on the basis of genetic process

in the living organisms.

There are

the following three main steps in Genetic Algorithm:

1. Selection

2. Crossover

3. Mutation

Selection is used to

recombine the population with the highest probability.

Crossover is a

genetic algorithm operator to mix the chromosomes with the extra chromosome

chosen to produce child chromosome from one generation to the next.

Mutation is a

genetic operator employed to maintain genetic diversity from one generation of

a population of genetic algorithm chromosomes to the next.

BODY:

In Hill

cipher there is a problem of finding the optimized key. In previous researches

key is obtained by trial and error method but this is not a good method of

finding a key. Here is a proper methodology of finding a key in Hill cipher so

doing this we have to apply genetic algorithm. In Hill Cipher every chromosome consists

of nine numbers. Each gene has a value “between” (0 to 255) which shows the

number of bytes. Since the ASCII value does not exceeds 255 so we cannot take

an integer as a modular expression. The matrix is transformed into

one-dimensional vector so we just search the ideal fitness which does not

contain equal value. Since the determinant is in the odd number, it is good for

Hill cipher. But in this case it will still to find until the determinant

reaches 1. The determinant has value 1 and it is suitable for the

Hill Cipher process. When the determinant is 1 it can bring the cipher text

back to the plain text and vice versa.

CONCLUSIONS:

In Hill

cipher which has 3*3 matrix in this matrix the searching key that has the

proper determinant takes time. If we perform this process by genetic algorithm

it will slow down the process of cryptography. Genetic algorithms greatly assist

the process of the encryption and the decryption on the Hill Cipher. This

process makes our problem solved and makes it easy and quick. It is a time

saving process.

In this study, we conclude that the genetic algorithm has a great and

valuable contribution when combined with the Hill Cipher method.

LITERATURE

CITED: