A new design of cryptosystem based on S-box and chaotic permutation M. A. Ben Farah 1 & R. Guesmi 1 & A. Kachouri 1 & M. Samet 1 Received: 9 April 2019 /Revised: 6 December 2019 /Accepted: 31 January 2020 # Springer Science+Business Media, LLC, part of Springer Nature 2020 Abstract In this paper, we present a new design of cryptosystem characterized by an optimized substitution box (S-box) and random permutation. Our proposed S-box is generated using a modified genetic algorithm. The crossover process is per- formed with sophisticated research using the best previous population. We use randomness and ergodicity of the logistic map to add complexity and robustness to our proposed method. Many tests proving the nonlinearity of our S-box have been carried out to demonstrate the efficiency of our algorithm. In the second part, we offer a new permutation algorithm based on a chaotic sequence generated from the logistic map. To show the performance of our proposition, we compare our results with previous algorithms. The results of its statistical analysis, like entropy value and correlation between adjacent pixels, show that the proposed image encryption scheme provides security for image encryption. The time speed of the proposed algorithm confirms the possibility of real-time implementation. Keywords S-box . Logistic map . Randomness . Nonlinearity . Optimization Multimedia Tools and Applications https://doi.org/10.1007/s11042-020-08718-8 * M. A. Ben Farah aminefrh5@gmail.com R. Guesmi ramzi.guesmi@gmail.com A. Kachouri abdennaceur.kachouri@enis.rnu.tn M. Samet mounir.samet@enis.rnu.tn 1 LETI Laboratory, National Engineering School of Sfax, Sfax University, B.P.W. 3038, Sfax, Tunisia