Image encryption based on the iterative fractional fourier transform and a novel pixel scrambling technique

A novel image encryption system based on the iterative fractional Fourier transform and the pixel scrambling technique is presented. During the procedure of image encryption, the ciphertext is randomly generated and the original image has been interpolated and divided into several equal sub-images. Via constructed the relationship between the ciphertext and the sub-images, a large number of phase functions are obtained as the keys of the scheme. Every part of the image can be recovered from the single ciphertext by their corresponding keys. The pixels scrambling technique is used to enhance the security of our scheme. By using the block encryption, the position of every sub-image will be a special element for decryption. Numerical simulations demonstrate the security and the flexibility of the proposed scheme.