基于3D-CS混沌系统的双DNA编码图像加密算法

目的为解决加密算法中明文与混沌系统密钥关联小,且置乱扩散不能同步进行造成的安全性低的问题。在结合Chebyshev和Sine映射的基础上,新建三维Chebyshev-Sine混沌映射系统(3D-CS),提出一种基于3D-CS混沌系统的双DNA编码图像加密算法。方法设定二进制与四进制双重DNA编码,利用约瑟夫环变换对经过二进制DNA编码的图像RGB各层进行位置索引,同时完成置乱和扩散,然后将混沌系统产生的序列值经过处理后进行四进制DNA编码,最后将2种DNA序列进行加法运算后解码得到密文。结果仿真实验表明,索引序列和混沌序列通过了随机性检验,密文各层NPCR值分别为99.63%,99.61%,99.59%,UACI值分别为33.43%,33.44%,33.40%,信息熵分别为7.9992,7.9991,7.9993。结论所设计的混沌序列相较于其他混沌序列有一定优势,针对提出的问题有效提高了加密算法的安全性,密文能有效地抵御各种统计攻击与差分攻击。

Image Encryption Algorithm Based on 3D-CS Chaotic System and Dual DNA Coding

The work aims to solve the low security problem caused by the small correlation between plaintext and chaotic system keys, and the synchronization failure of scrambling and diffusion. On the basis of combining Chebyshev and Sine mapping, a 3D chaotic mapping system (3D-CS) was constructed. A double DNA encoding image encryption algorithm based on 3D-CS chaotic system was proposed. The binary and quaternary dual DNA encoding was set. The Joseph ring transform was used to index the position of RGB layers of image encoded by binary DNA to complete both scrambling and diffusion synchronously. Then the sequence values generated by the chaotic system were processed and encoded with quaternary DNA. Finally, the two DNA sequences were added and decoded to obtain the ciphertext. Simulation experiment showed that index sequences and chaotic sequences were tested by randomness. The NPCR values of each layer of ciphertext were 99.63%, 99.61% and 99.59%, and the UACI values were 33.43%, 33.44% and 33.40%, respectively. The entropy of information were 7.9992, 7.9991 and 7.9993. Compared with other chaotic sequences, the chaotic ciphertext has some advantages over other chaotic system sequences. It can effectively improve the security of encryption algorithm and resist statistical attacks and differential attacks.