Image encryption using eight dimensional chaotic cat map

In recent years, a large number of discrete chaotic cryptographic algorithms have been proposed. However, most of them encounter some problems such as lack of robustness and security. In this paper, we introduce a new image encryption algorithm based on eight-dimensional (nonlinear) chaotic cat map. Encryption of image is different from that of texts due to some intrinsic features of image such as bulk data capacity and high redundancy, which are generally difficult to handle by traditional methods. In traditional methods the key space is small and the security is weak. The proposed algorithm tries to address these problems and also tries to enhance the encryption speed. In this paper an eight dimensional chaotic cat map is used to encrypt the intensity values of pixels using lookup table method thereby significantly increasing the speed and security of encryption. The proposed algorithm is found to be resistive against chosen/known-plaintext attacks, statistical and differential attacks.