A new method for encrypting a color image in one channel based on triple-phase encoding is presented.The colors are converted from RGB to HSI,so the I component can be used as the original image which can be encoded with triple-phase.The H component can be used as the first phase,the second phase is obtained by S component encryption using double-image encryption method based on iterative fractional Fourier transform(FrFT),and the third phase is obtained from the difference between the output phase of trans...