Image Encryption Algorithm Based on Chaos and Contourlet Transform

A new algorithm based on chaos and Contourlet is presented in this paper for image encryption. Firstly, the image is decomposed with contourlet into several sub-bands. Three bands are selected to encrypt. At the same time, we divide the bands into non-covered blocks, respectively. Secondly, two natural chaotic sequences are created with the key. With one chaotic sequence, the encryption template used to adjust transform coefficients is made. Finally, after inverse contourlet transform, the image matrix is transformed to an encrypted image by Magic Cube Transformation. The decryption operation is the reverse process. The experimental results suggest that the algorithm proposed not only has good encryption ability, but also can withstand the attack of JPEG compression, the effects of noise and cropping to some extent.