BMP图按位提取工具。可以打开任意一幅位图，只保留其图像区中的某几位，其余用0或1填充，得到新的图像并保存。-BMP map extract tool by bit. Any one can open a bitmap, only retain the image area of a few, the rest filled with 0 or 1, get new image and save.

用AES算法实现BMP图像加密，只能加密BMP的文件，速度很快-BMP images with the AES encryption algorithm