In the view of the security of the remote transmission of the CAD drawing,the general principle of watermark is studied,and the structure of image file and DXF file is analyzed.

• 针对CAD图纸远程传输信息安全的问题,根据数字水印的原理对图像数据文件结构及DXF文件结构进行了分析,给出了DXF文件基于信息替代的数字水印算法,实现了CAD图纸远程传输过程中的信息隐藏。