文摘
In recent years, hyper-chaos systems have been widely used in image cipher design. So far, a number of hyper-chaos-based image ciphers have been cryptanalyzed, but many others have not been effectively attacked like an image cipher with a classic bi-modular architecture of permutation and diffusion. This study cryptanalyzes this cipher. It is demonstrated that the cipher can be broken by differential attack with multiple pairs of special plain/cipher images.