基于多混沌系统的图像分组密码设计

对于混沌系统数字化后引起的混沌性能下降，结合Logistic映射和分段线性混沌映射（PLCM）及定义在(0，1)上的移位映射设计了一个混沌随机数发生器，通过不同混沌系统迭代，生成的随机序列由四个混沌轨道确定，具有良好的随机性和在有限精度实现条件下周期大的特点；并基于此混沌随机数发生器提出了一种分组图像加密算法，该算法具有较强的鲁棒性，加密图像在部分受损或缺失后，仍有较好的恢复效果，该算法具有控制参数较多、密钥空间大、对密钥十分敏感的优点，对多种攻击手段具有较好的免疫性。

Design of image group code based on chaotic systems

Chaotic capability will decline after digitalizing chaotic system. Aiming at this question, a chaotic random number generator based on Logistic mapping was presented in this paper, Piecewise Linear Chaotic Mapping (PLCM) and shift mapping defined on (0,1). Through the iterations of different chaotic systems, the generating random sequence was confirmed by four trajectories. Therefore, it has better random characteristic and longer cycle under finite precision. A group image encryption algorithm based on this chaotic random number generator is also presented. This algorithm has stronger robustness. The restore effect is also well while the encryption image is partly damaged or deleted. This algorithm has more control parameters and a large space of keys. It is sensitive to key and it has excellent performance against attacks.