Single-channel color image encryption based on the multiple-order discrete fractional Fourier transform and chaotic scrambling

A new color image encryption method using multiple-order discrete fractional Fourier transform (MODFrFT) and chaotic scramble is proposed. A color image is converted from the standard RGB space into the YCbCr space and the complex number mode featured as a real part and an imaginary one is used in this encryption method to alleviate the transmission load. Human vision is more sensitive to the Y component than to the other two components in the YCbCr color space and this color format is used for encrypting the color image. Chaos is also introduced to scramble the matrix in the fractional Fourier domain. The numerical simulations demonstrate the validity and efficiency of this scheme and the robustness of the method against occlusion attack is examined.