Optical encryption of gray image based on CS and CGH with double chaotic system

Abstract

In this paper, a novel image encryption algorithm is proposed by combining Logistic chaotic map, 4D NHS hyperchaotic system, compressed sensing (CS), computer generated hologram (CGH) and two-dimensional discrete cosine transform (DCT). Firstly, the gray image is sparse represented by two-dimensional discrete cosine transform (DCT). The sparse matrix obtained by index sort scrambling is scrambled. For further encryption, the pixel scrambling uses the Logistic chaotic system to generate the scrambling vector. Subsequently, CGH encryption was performed and the Logistic chaotic map and 4D NHS hyperchaotic system were used as double keys to obtain the final encrypted picture.