We present a novel permutation algorithm for fast encryption of a large amount of data, such as 3D images and real-time videos. The proposed P-Box algorithm takes advantage of Gray code properties and allows fast encryption with high information diffusion. The algorithm is optimized for integer q-bit operations (q ¼ 8; 16; 32; . . .), allowing a direct implementation in almost any hardware platform, while avoiding rounding errors of floating- point operations. By combining the P-Box with chaotic S-Box based on the logistic map, we design a complete, highly secure and fast cryptosystem.