Abstract: An encryption method for image watermarking using multiple cellular automata (CA) was proposed in order to solve the security problem, which is faced by most of the existing reversible watermarking methods based on histogram shifting (RW-HS). The proposed method made a security analysis of RW-HS from three aspects including side information, watermarks and watermarked images. Based on this, three CAs with different rule numbers were employed to build a multiple encryption model and thus to generate the encrypted watermarked images. Experimental results illustrate that the proposed method is highly secure in terms of key space, histogram distribution, correlation, information entropy and gray scale change, and that it effectively solves the security problems of RW-HS.