Abstract: A digital image encryption algorithm，dual scrambling based on chaos of pixel position and pixel value，is presented.The algorithm uses Logistic chaotic sequences to scramble digital image pixel positions and then scramble digital image pixel values by using Logistic chaotic sequences again.Consequently，dual scrambling of pixel position and value based on chaos is completed and the algorithm improves the traditional image encryption algorithm of image scrambling based on chaos.Experimental results show that the effect of the proposed method is perfect and it outperforms the traditional image encryption algorithm based on Logistic chaos sequences in digital image pixel dots.

Key words: image encryption, Logistic chaotic sequences, dual scrambling, pixel position, pixel value

摘要： 提出了一种数字图像像素位置与像素值双重置换的混沌加密算法，对常用的基于混沌的数字图像加密技术进行了改进，利用Logistic混沌映射对数字图像像素位置进行置换加密，然后再次利用Logistic混沌映射对数字图像像素值进行置乱，从而达到对像素位置和像素值双重加密的效果。仿真实验表明：其加密效果优于利用Logistic混沌序列对数字图像像素点置乱的加密技术。

关键词: 图像加密, Logistic混沌序列, 双重置换, 像素位置, 像素值