Image encryption algorithm based on a novel 2D logistic-sine-coupling chaos map and bit-level dynamic scrambling

Abstract

This paper develops a new image encryption algorithm based on a novel two-dimensional chaotic map and bit-level dynamic scrambling. First, multiple one-dimensional chaotic maps are coupled to construct a novel two dimensions Logistic-Sine-coupling chaos map (2D-LSCCM). The performance analysis shows that the 2D-LSCCM has more complex chaotic characteristics and wider chaotic range than many extant 2D chaos maps. Second, original image matrix combines with hash algorithm SHA-256 to generate a hash value. The initial values of 2D-LSCCM are generated based on the hash value. Third, the original image matrix is divided into multiple sub-matrices by wavelet transform, followed by scrambling by an improved Knuth shuffle algorithm. Fourth, the scrambled multiple sub-matrices are stitched into an image matrix of $M\times N\times 3$ and converted into a binary matrix. The chaotic sequence generated by 2D-LSCCM is introduced as a control sequence to control the bit-level scrambling of pixel points, which realizes the bit-level dynamic scrambling. Finally, the diffusion operation is performed by parameter par and chaotic sequence to obtain the final encrypted image. The algorithm security analysis and simulation examples demonstrate the effectiveness of the proposed encryption scheme.