多媒体信息安全.pdfVIP

多媒体信息安全 多媒体信息安全 信息科学与工程学院 付冲 多媒体信息安全 多媒体信息安全 多多媒媒体体信信息息安安全全 课程体系 � 混沌密码学基础 � 基于混沌的图像加密技术 MPEG MPEG � MMPPEEGG 视频编码基础 MPEG � MPEG MMPPEEGG 视频加密技术 Permutation-Diffusion Architecture Permutation-Diffusion Architecture PPeerrmmuuttaattiioonn--DDiiffffuussiioonn AArrcchhiitteeccttuurree • There are two iterative stages in the chaos-based image cryptosystem: permutation and diffusion. n r o u n d m r o u n d Perm utation D iffusion Plain image (Pixel position transformation) (Pixel value transformation) Cipher image Chaotic Map Chaotic Map Permutation Key Diffusion Key Permutation-Diffusion Architecture Permutation-Diffusion Architecture PPeerrmmuuttaattiioonn--DDiiffffuussiioonn AArrcchhiitteeccttuurree • The permutation stage shuffles the pixels in the image, without changing its value. • In the diffusion stage, the pixel values are modified sequentially and the modification made to a particular pixel depends on the accumulated effect of all the previous pixel values so that a slight change in one pixel is spread out to all subsequent pixels in the image. • To dec