Abstract: In order to ensure the security and reliability of image in the process of information transmission,ordinary scrambling-diffusion encryption algorithm can not meet the security and efficiency problems nowadays.In this paper,the plaintext is transformed into hash value as the initial value of chaos,and four chaotic sequences are generated by fractional order Chen hyperchaos.Firstly,three-dimensional Arnold mapping is used for bidirectional parametric scrambling,and then hyperchaotic S-box is designed for substitution.Finally,chaotic cellular automata is used to circulate and diffuse,thus achieving a complete encryption process combining scrambling,substitution and diffusion (DSD).The algorithm has large key space,high key sensitivity,uniform statistical histogram of ciphertext,low correlation between adjacent pixels of ciphertext,high security and strong resistance to differential attack,and information entropy is close to ideal value.The algorithm can achieve a high level of security without multiple iterations,and the encryption security and efficiency are significantly improved.

Key words: bidirectional parametric, chaotic cellular automata, Fractional Chen hyperchaos, hyperchaotic S-box substitution, three-dimensional Arnold map