Color image encryption by using the rotation of color vector in Hartley transform domains

We propose an algorithm to encrypt color image by using the rotation of color vector based on discrete Hartley transform. The three component images (red, green and blue) of color image are regarded as the axes of Cartesian coordinates. Two random angle shifts are introduced to rotate the color vectors composed by the three color components in discrete Hartley transform domains in image encryption process. The corresponding rotation shifts of the two angles can serve as the key of the scheme. Moreover the encrypted image is encoded with real number. Some numerical simulations have demonstrated the possibility of the proposed scheme.