Hybrid image encryption scheme based on hyperchaotic map with spherical attractors

Abstract Existing chaotic encryption schemes primarily focus on single types of images, making the design of hybrid image encryption schemes more suitable for practical applications. In this paper, a hyperchaotic map with a spherical attractor is proposed, which is constructed using spherical coordinates. Dynamical analyses reveal that the hyperchaotic map exhibits global hyperchaos and high complexity, making it capable of generating more complex chaotic sequences suitable for image encryption. A hybrid encryption scheme based on a hyperchaotic map is proposed for two-dimensional (2D) images, three-dimensional (3D) models, and 3D point clouds. Firstly, the pixels of 2D image and the coordinate data of 3D image are fused into a plaintext cube, which is combined with Hash-512 to obtain the initial value of the hyperchaotic map. Chaotic sequences are utilized for cube space internal confusion and dynamic cross-diffusion. The encrypted images demonstrate high information entropy, and the test results show that the encryption scheme effectively protects the images. The proposed hybrid image encryption scheme provides an efficient solution for securing various types of images.