Visual image encryption scheme based on inter-intra-block scrambling and weighted diffusion

• Published in: The Visual computer Vol. 40; no. 2; pp. 731 - 746
• Main Authors: Li, Chunlai, Zhang, Yan, Li, Haodong, Zhou, Yang
• Format: Journal Article
• Language: English
• Published: Berlin/Heidelberg Springer Berlin Heidelberg 01.02.2024
• Subjects: Artificial Intelligence; Computer Graphics; Computer Science; Image Processing and Computer Vision; Original Article; Robust hyper-chaos; Inter-intra-block scrambling; Weighted diffusion; Visual encryption
• ISSN: 0178-2789; 1432-2315
• DOI: 10.1007/s00371-023-02812-2

This paper presents an image encryption scheme with data and appearance security, by adopting inter-intra-block scrambling and weighted diffusion. The 2D robust hyper-chaotic map with flexible geometric distribution and rich hyper-chaotic parameter space is employed to generate the key stream for encryption, by considering the characteristics of plaintext. The plain image is first preprocessed by Huffman coding for getting compressed image. Then, the compressed image is divided into four sub-blocks and is further permuted by the designed inter-intra-block scrambling scheme, which can improve the scrambling effect by making the pixel far away from the original adjacent pixels. After that, a weighted diffusion method strongly related to plaintext and key stream is introduced to diffuse the shuffled image to obtain the noise-like cipher image. And in pursuit of higher security, the meaningless noise-like image is embedded into host image to create the visually meaningful cipher image. A series of experiment tests and analyses are carried out to further demonstrate the excellent performances of the encryption scheme.