Abstract: Memrisitive cellular automata is a kind of new cellular automata,and its operation can produce transformation of cells state and make its links changed．We analyzed the varied change of cellular automata and the links between the cells,then we designed a new encryption algorithm:use a W×H cells automata arrays as Public-Key,the initial states and respond time as Private-Key,get the links between the cells as a encryption matrix．Meanwhile,we used the pixel value replacement method to encrypt a image．This algorithm has the advantage of confusion and diffusion properties,besides,it owes its advantage in fine security,large key space and diffusion．The algorithm analyzes turn out that this method is of high encryption efficiency and security,which could just meet the digital image demands on security．

Key words: Memristive cellular automata,Image encryption,Pixel value replacement