A Chaos-based Image Encryption Scheme Using Multimodal Skew Tent Maps

Chaotic multimodal skew tent maps are constructed to design an efficient chaos-based image encryption scheme with an efficient permutation-diffusion mechanism, in which permuting the positions of image pixels incorporates with changing the grey values of image pixels to confuse the relationship between cipher-image and plain-image. In the permutation process, a multimodal skew tent map is utilized to generate one chaotic orbit used to permute the image pixel positions, while in the diffusion process, another two multimodal skew tent maps are employed to yield two pseudo-random grey value sequences for designing a two-way diffusion process. The yielded grey value sequences are not only sensitive to the control parameters and initial conditions of the considered chaotic maps, but also strongly depend on the plain-image processed, therefore the proposed scheme can resist statistical attack, differential attack, known-plaintext as well as chosen-plaintext attack. Experimental results are carried out with detailed analysis to demonstrate that the proposed image encryption scheme is highly secure thanks to its large key space and robust permutation-diffusion mechanism.