了解了24位BMP图像的相关结构后，就要对24位的BMP图像进行加密，因为BMP 图像是由像素组成，每个像素有三个字节，每个字节有8个二进制位组成，因此，改变最低位将不会影响图像的视觉效果。我们将最低位提取出来与高七位进行关联，利用密钥来进行加密，这样就达到了对文件进行嵌入水印的操作。-Understanding of 24 BMP images related to the structure, it is necessary for 24 of the BMP image encryption, because the BMP image by pixels, each pixel has three bytes, each byte has 8-bit binary components Therefore, change will not affect the lowest visual images. We will extract the lowest association with the high-7, the use of keys for encryption, so that the documents met the watermark embedding operation.