针对加密算法对明文敏感性较低的问题, 提出了一种基于混沌系统的新型图像加密算法。采用SHA256函数对明文图像进行计算得到初值, 将初值代入混沌系统生成伪随机序列, 进一步使用该序列完成对明文图像的置乱。使用并行扩散机制对置乱图像进行第一轮扩散, 在此基础上利用DNA动态编码技术进行第二轮扩散。对DNA矩阵解码得到二进制矩阵, 进一步转化为十进制矩阵, 得到加密图像。进行了计算机仿真分析和对比, 通过对统计特性、差分特性、信息熵、密钥和鲁棒性的分析与测试, 表明该算法安全性较好且易于实现, 具有较大的应用前景。

In order to make the encryption algorithm more sensitive to plaintext, a new image encryption scheme based on chaotic system is proposed. Plain image is calculated by hash function and the initial key is got, and chaotic system generates pseudo random sequence with the initial key. Plain image is permutated by the sequence further. The permutated image is diffused for the first round by the parallel diffusion mechanism. Based on that, the second round diffusion using the dynamic DNA coding technology is completed. The encrypted image is given by decoding the obtained final DNA matrix. The simulation results show that the algorithm has the advantages of simple structure, high security and is easier to achieve, so it has great application prospects.