AMCSFFT-CIE: Alternate Multi-dimensional Chaotic Structure and Fast Fourier Transform based Novel Approach to Color Image Encryption

: Low-dimensional chaotic maps are used for encrypting images because of their simplicity and low implementation cost. However, such chaotic systems are less secure and are slow in encryption speed as compared to multi-dimensional chaotic systems. This paper proposes the combination of spatial domain and frequency domain for image encryption. The proposed combination uses Four-dimensional chaotic map Lorenz System (LS) for key generation and alternate logistic structure for permutation-diffusion process. Initially, Lorenz System (LS) generates the security key using matrices color image’s R, G, and B components. Secondly, one dimensional and two dimensional chaotic structures are used to generate a chaos matrix i.e. the two logistic maps are iterated alternately for diffusing the matrix. Finally, the diffused plain image matrix is encoded into the phase and amplitude of the composite function which is encrypted with white noise distribution by using the fast Fourier transform. The simulated outcomes describe that the proposed approach increases the key space value, encryption speed and resists brute force attacks.