为增强加密算法的安全性，解决Sine映射和一维无限折叠迭代混沌映射（iterative chaotic map with infinite collapses, ICMIC）映射存在的周期性问题，提出了二维映射结合Z形螺旋置乱和DNA编码的多阶段加密算法。首先，Sine映射和ICMIC映射结合得到新的混沌映射SUIM（Sine union ICMIC mapping）；加密算法采用SHA-512从明文图像中生成密钥，接下来利用提出的Z形螺旋变换和双向Zigzag变换对明文图像进行置乱；改进边界像素替换来增强图像的抗攻击性；最后进行像素随机扩散和DNA级二次扩散处理。结果表明，所提加密算法具有较高的信息熵，抗差分攻击性能更好，相邻像素相关性更低，进一步保障了图像数据的安全性和隐私性。

To enhance the security of encryption algorithms and solve periodicity problem with Sine mapping and ICMIC(iterative chaotic map with infinite collapses) mapping, a multi-stage encryption algorithm combining 2D mapping with Z-shaped spiral scrambling and DNA coding was proposed. Firstly, a new chaotic map SUIM(Sine union ICMIC mapping) was obtained by combining Sine map and ICMIC map. The encryption algorithm mainly used SHA-512 to generate key from the plaintext image, used the proposed Z-shaped spiral transform and bidirectional Zigzag transform to scramble plaintext images, and improved boundary pixel replacement to enhance image resilience. Subsequently, pixel random diffusion and DNA level secondary diffusion processing were performed. Results show that the proposed encryption algorithm has higher information entropy, better resistance to differential attacks, lower correlation between adjacent pixels, and further guarantees the security and privacy of image data.