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

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.

Automated summary

This paper presents an image encryption scheme that ensures data and appearance security through inter-intra-block scrambling and weighted diffusion. The scheme utilizes a 2D robust hyper-chaotic map to generate a key stream for encryption, taking the characteristics of the plaintext into account. The compressed image is processed through Huffman coding, then divided into sub-blocks and further permuted through the designed scrambling scheme to improve the scrambling effect. A weighted diffusion method that is closely related to the plaintext and key stream is introduced to diffuse the shuffled image and create a noise-like cipher image for enhanced security. This encryption scheme demonstrates excellent performance through a series of experimental tests and analyses.