LSIE: a fast and secure Latin square-based image encryption scheme

The current paper proposes LSIE, a fast and secure Latin square-based image encryption scheme using SHA256 hash function and chaotic systems. LSIE uses a 3-tier architecture consisting of diffusion-confusion-diffusion based on Latin squares to design an efficient cryptographic algorithm. Firstly, the initial values and parameters of the 3D exponent chaotic map (3D-ECM) is obtained from the SHA256 hash value of the external secret key and the plain image. Next, two orthogonal Latin squares are constructed using chaotic sequences generated by the 3D-ECM. In the first diffusion phase, one of the Latin squares is considered as a key image to Exclusive-OR (XOR) with the plain image. In the confusion phase, a 2D permutation based on the orthogonal Latin squares is presented to permute pixel positions of the diffused image. In the second diffusion phase, another Latin square is considered as a key image to XOR with the permuted image. The analysis and simulation results indicate that the proposed LSIE could efficiently resist common security attacks, as also that it is a fast method for real-time applications. The MATLAB source code of the proposed LSIE is available at the URL: https://github.com/EbrahimZarei64/LSIE.