Chaotic Dynamic S Boxes Based Substitution Approach for Digital Images

In this paper, we propose an image encryption algorithm based on the chaos, substitution boxes, nonlinear transformation in galois field GF(2 8 ) and Latin square. Initially, the dynamic S-boxes are generated using Fisher-Yates shuffle method and piece-wise linear chaotic map. The algorithm utilizes advantages of keyed Latin square and affine-power-affine transformation to substitute highly correlated digital images and yield encrypted image with valued performance. The chaotic behaviour is achieved using Logistic map which is used to select one of thousand S-boxes and also decides the row and column of selected S-box. The selected S-box value is transformed using nonlinear affine-power-affine transformation. Along with the keyed Latin square generated using a 256-bit external key, used to substitute secretly plain image pixels in cipher block chaining mode. To further strengthen the security of algorithm, round operation are applied to obtain final ciphered image. The experimental results are performed to evaluate algorithm and the anticipated algorithm is compared with a recent encryption scheme. The analyses demonstrate algorithm’s effectiveness in providing high security to digital media.