REVIEWDynamic Key Matrix of Hill Cipher Using Genetic Algorithm ABSTRACT: This is atechnique in which we make the implementation of Hill cipher easy by usinggenetic algorithm.
In Hill cipher a matrix is designed to perform encryptionand decryption. We insert some integer number in the rows and columns of thismatrix. The wrong determinant result of this matrixcannot be used in the process because while decryption it produces an incorrectplain text. Genetic algorithms has the optimized way to finding the key whichis used for encryption and decryption on the Hill Cipher Algorithm. By implementingthis algorithm the searching of the key in Hill Cipher will be easily done in ashort time. Genetic Algorithm perform more efficient if it is combined withHill cipher.
INTRODUCTION: Hill cipheris an arithmetic technique in cryptography that is why it uses a symmetric keyto convert plain text into cipher text. Symmetric key is a system that has thesame kind of keys in encryption and decryption. But we must have to inverse thekey before decrypting a cipher text into plain text. The major part in a matrixthat is used in Hill cipher is the multiplication between the matrix and theinverse of a matrix. Now we will know about the genetic algorithm that what isgenetic algorithm and how it works. Genetic Algorithm is a computationalalgorithm and basically this algorithm is built on the basis of genetic processin the living organisms.
There arethe following three main steps in Genetic Algorithm:1. Selection2. Crossover3. MutationSelection is used torecombine the population with the highest probability.Crossover is agenetic algorithm operator to mix the chromosomes with the extra chromosomechosen to produce child chromosome from one generation to the next.Mutation is agenetic operator employed to maintain genetic diversity from one generation ofa population of genetic algorithm chromosomes to the next. BODY: In Hillcipher there is a problem of finding the optimized key.
In previous researcheskey is obtained by trial and error method but this is not a good method offinding a key. Here is a proper methodology of finding a key in Hill cipher sodoing this we have to apply genetic algorithm. In Hill Cipher every chromosome consistsof nine numbers. Each gene has a value “between” (0 to 255) which shows thenumber of bytes. Since the ASCII value does not exceeds 255 so we cannot takean integer as a modular expression.
The matrix is transformed intoone-dimensional vector so we just search the ideal fitness which does notcontain equal value. Since the determinant is in the odd number, it is good forHill cipher. But in this case it will still to find until the determinantreaches 1. The determinant has value 1 and it is suitable for theHill Cipher process. When the determinant is 1 it can bring the cipher textback to the plain text and vice versa. CONCLUSIONS: In Hillcipher which has 3*3 matrix in this matrix the searching key that has theproper determinant takes time. If we perform this process by genetic algorithmit will slow down the process of cryptography. Genetic algorithms greatly assistthe process of the encryption and the decryption on the Hill Cipher.
Thisprocess makes our problem solved and makes it easy and quick. It is a timesaving process.In this study, we conclude that the genetic algorithm has a great andvaluable contribution when combined with the Hill Cipher method. LITERATURECITED: