利用构造三角形的思想,提出了一种新的可逆二维映射,能够加密任意形状图像。映射过程是:首先利用原图像构造等腰三角形。三角形的第1行有1个像素,第2行有2个像素,其他行像素数目依次增加。接着,将三角形奇数行的像素依次插入到偶数行像素间。然后,将这些像素连接起来。再对照原图像的特征,将行折叠,得到和原图大小一样的图像。映射过程置乱了像素的位置,是可逆的,可用于加密图像。按起点不同,映射分为左映射和右映射。加密时,2种映射的次数可作为密钥。推导出映射的数学表达式,设计了密钥产生的方法,分析了图像加密算法的安全性问题。仿真验证了算法的有效性。分析表明,该映射可加密压缩文件甚至任意长度的数据集。
By constructing an isosceles triangle,the paper proposes a new invertible two-dimensional map which can encrypt rectangle images.by processing image stretch-and-fold.Firstly,pixels of plain-image are constructed to a virtual isosceles triangle where the pixels of each row are added one by one.Then the pixels of the odd row are inserted into adjacent two pixels of the even row,and the triangle is stretched to a line of pixels.Lastly,the line is folded over to a new image with the same size to the plain-image...