A Novel Color Image Cryptosystem Using Chaotic Cat and Chebyshev Map

With the advancement of multimedia and real-time networks, a vast number of digital images are now stored and transmitted over public networks. A lot of researches of chaos-based image encryption technologies have been done. However, the performance of conventional encryption algorithm is not satisfying when used to color image. In this paper, we propose an improved chaos-based color image cryptosystem which significantly increases the efficiency and enhances the security performance. In this algorithm, firstly a color image is divided into three color channels. Then a bit-level permutation is performed in each channel, hence diffusion scheme is introduced into permutation stage. Meanwhile, we provide optional and partial cipher function. Detailed analysis of security performance and results show great advantages in speed, key space, correlation, information entropy ,etc.