中文摘要：

为了增强对数字彩色图像信息安全的有效保护,给出一种基于医院信息系统（HIS）的彩色图像加密算法.首先,使用混沌序列控制对亮度层的位平面排序;然后,对排序后每一个位平面采用改进的置乱算法;最后,恢复到像素平面以完成加密.该算法相比于基于RGB系统的加密算法,减小了时间复杂度,且不降低加密算法的安全性能.仿真结果表明：该算法的密钥空间大、秘钥敏感性强,对统计分析和剪切攻击具有较好的抵抗能力.

英文摘要：

In order to protect digital color image′s safety,one color image encryption algorithm for hospital information system（HIS）space is proposed in this paper.First of all,use chaotic sequence to control the bit-plane of luminance layer,then use the improved scrambling algorithm on each sorted bit-plane,finally,retrieve them into pixel plane.This algorithm has less time complexity compared to the traditional algorithm in RGB space,meanwhile,has good safety performance.The simulating results show that this algorithm has a large space of keys,good key sensitivity,also has ability to resist the statistical analysis and shearing attacks.