中文摘要：

对一种改进的基于DNA编码和混沌映射的图像加密方法进行了安全性分析，原算法的核心思想是明文图像的DNA编码矩阵与混沌映射产生的随机矩阵的DNA编码矩阵求和，然后再对这个和矩阵中的元素随机求补即得密文图像；经深入分析发现原算法的安全性完全依赖于混沌映射产生的随机矩阵，而随机矩阵的生成与明文图像或对应的密文图像没有任何关联，从而能用选择明文攻击的方法获得等效密钥，破译目标密文，解密出目标明文，理论分析和仿真实验验证了选择明文攻击策略的可行性；同时指出了原算法存在的另外两个安全缺陷，最后简要讨论了提高该算法安全性的一些改进措施。

英文摘要：

This paper first introduced an image encryption algorithm based on DNA coding and chaotic maps, analyzed its security and found that the essence of the proposed algorithm was to add up DNA encoding matrix of the plain text image and that of the random matrix generated by chaotic maps and obtained the cipher image by complement operation of the sum matrix. Through in-depth analysis, it found that the security of the algorithm was completely dependent on the random matrix produced by chaotic mapping, which had no correlation with the plain text image or the corresponding cipher text image. Therefore, it obtained the equivalent key with chosen plaintext attacks to decipher the target plain text image and decrypted the target cipher text image. Both mathematical analysis and analogue simulation experimental results verify the feasibility of the proposed chosen plaintext attack strategies. In addition,it reported another two other security defects of the introduced algorithm and finally discussed some possible methods to improve its security.