Color image encryption in YCbCr space

Nowadays, with the development of Internet technology and the improvement of safety awareness, image encryption technique has become very important, especially for color image encryption. The direction of research is focused on the RGB color space. There are few researches in other color spaces, such as HSV, L*a*b*, YCbCr. In this paper, we propose a color image encryption method in YCbCr color space. There is much information in Y channel but little information in Cb and Cr channel. Using this feature, we choose different encryption schemes. We first convert the color space from RGB to YCbCr. Then we encrypt the three channels separately. In Y channel, with Arnold cat map, we can do the preliminary image confusion, and then we use three-dimensional Lu chaotic map to do the further image diffusion. In Cb and Cr channels, we use DNA encoding and 1D Logistic chaotic map. Experimental results show that our color image encryption works well, our method in YCbCr space can compare with the RGB and L*a*b* space, and can resist brute-force attacks, differential attacks. The most prominent point is that the speed of encryption and decryption is much faster.