Color Image Encryption Based on Fractional Fourier Transform

In order to cope with the shortage of present image encryption algorithm, a novel color image encryption algorithm based on chaotic system and fractional Fourier transform is proposed in this paper. The image encryption process includes three steps: first the RGB color components of the input image are permuted and transformed into YCbCr color space. Then every component of YCbCr is encrypted by employing Fractional Fourier domain double random phase. Finally the every components of confusion image is encrypted by using confusion matrix which is generated by chaotic system, and the cipher image is obtained by composing the encrypted contents. The security of the proposed algorithm depends on the sensitivity to the randomness of phase mask, the orders of FRFT and the initial conditions of chaotic system. Theoretical analysis and experimental results demonstrate that the algorithm is favorable.