Construction of dynamical S-boxes based on piecewise map: Image encryption approach

Abstract

Many cryptographic schemes have been implemented, using the connection between chaos and cryptography. Substitution box (S-box) is one of the most successful examples of these strategies. However, most S-box design schemes contain a fixed point, which may cause a security issue for cryptographic primitives. In this paper, to achieve a low automatic correlation, a dynamic S-box is constructed based on a piecewise map. Lyapunov exponent has been calculated analytically by using the obtained invariant measure. Then, an image encryption algorithm based on a designated S-box and a trigonometric chaotic map is proposed. Theoretical and experimental results have indicated that the proposed algorithm is included large keyspace, high sensitivity to key, and robust to attacks.