Image Encryption Using Arnold Transform Technique and Hartley Transform Domain

This paper proposes an image encryption method to encrypt a covert image by combining the Arnold transform technique in the space domain and the Hartley transform method in the frequency domain. First, transform a covert image into form eight binary images by decimal value to eight-digit binary operation. Then, transform eight binary images into form eight binary scrambled images by the Arnold transform, respectively. And then, recombine the sequence of the eight binary scrambled matrices into a scrambled matrix with 256 gray levels according to the specific order. Finally, derive an encrypted image from the scrambled image by the Hartley transform. Simulations show that the proposed method has higher image scrambling degree, more security and has robustness against occlusion and salt & pepper noise attacks.