The bidders doubly encrypt the bidding files with the project certificate and the server certificate so that both tenderee and server ca n ' t open the bidding files before the unsealing moment . this step assures the bidding files safe so as to enable the tendering work to go on wheels . liu weiwei ( computer science and application ) directed by prof . cheng jingyun 投标人利用项目证书和站点服务器证书对投标文件进行双重加密，以避免招标人和站点服务器任何一方在开标之前打开投标文件，从而确保了投标文件的安全，防止有人从中牟利，泄漏信息，破坏招投标工作的顺利展开。
