An Efficient Quasigroup Based Image Encryption Using Modified Nonlinear Chaotic Maps

This work proposes an efficient quasigroup based image encryption using modified nonlinear chaotic maps, which has good scrambling properties. There are three sets of nonlinear chaotic maps used in the proposed scheme to get good confusion and diffusion properties. The scheme includes, permutation and XORing with first chaotic key. Quasigroup byte substitution uses the second secret key and performs substitution operation to convert the input into cipher. Horizontal diffusion by XORing with adjacent pixels, nonlinear diffusion and vertical diffusion by XORing with adjacent pixels enhance sensitivity to plaintext and key thereby improve the security level. The security and performance analysis of the proposed image encryption has been performed using the histograms, correlation coefficients, information entropy, key sensitivity analysis, differential analysis and key space analysis. Results suggest that the proposed image encryption scheme is secure, demonstrates the large key space, the good sensitivity to the key, the perfect confusion and diffusion properties. It may be used for the secure image communication applications.