一种混沌双变换图像加密算法的分析与改进

对一种基于位置和灰度双重变换的混沌图像密码算法进行了密码分析，找出了一种基于选择明文攻击的密码破解方法，进而提出了一种改进的混沌双变换型图像加密算法，并对改进算法进行了安全性分析和仿真实验．理论分析和实验结果表明，改进算法能抵御选择明文攻击，且其多项其它密码学性能也有明显的改善．

The Analysis and Improvement of a Chaos-based Dual Transformation Image Encryption Algorithm

An analysis is made on an image encryption algorithm based on chaotic Logistic system and dual transformation, and a method to decode the cipher-image based on chosen plaintext attack is found out. An improved algorithm based on chaotic Logistic system and dual transformation is proposed. Simulation experiments and security analysis are performed. The theoretical analysis and experimental results show that the improved algorithm can resist chosen plaintext attack, and has better cryptographic performances in many other aspects.