Generalized Affine Transformation Based on Circulant Matrices

The secure transmission of any form of data over a communication medium is prime important across the globe or in research arena. Cryptography is a branch of cryptology and it provides security for data transmission between any communicating parties. The Hill cipher is one of the symmetric key substitution algorithms. Hill Cipher is vulnerable to known plaintext attack. This paper presents an enhancement to the Hill cipher by utilizing the circulant matrices. The proposed technique shares a prime circulant matrix as a secret key and we choose a non-singular matrix as a public key in such way that the determinant of the coefficient matrix is zero. Computational cost shows that the proposed technique isefficient and it thwarts all the security attacks.