Two Enhanced Feistel Steps for Medical Image Encryption

In this paper, we will develop a new method for color image encryption, based on an improved Feistel scheme designed from chaotic maps. After having vectorized the image, we subdivide the vector into a block of even size, we will apply two rounds of improved Feistel, which implements a chaotic permutation and a linear transformation provided by a not necessarily invertible square matrix. finally, a diffusion function is performed to overcome the differential attack. the effectiveness of our approach is proven by security test, namely correlation, histogram, entropy and differential parameters.\begin{equation*}{\mathbf{Notation}}\left\{ {{{\mathbf{G}}_{\mathbf{t}}}{{\mathbf{ = }}^{\mathbf{Z}}}{{\mathbf{/}}_{{\mathbf{tZ}}}}} \right.{\mathbf{ring}}\end{equation*}