This invention discloses a safety authenticating method for PC customer end including PC customer end presents registration request to a service via ID number and cipher, the server makes the first authentication based on customer ID number and the cipher to generate a field of reauthentication if it's passed to be fed back to PC customer end along with the finished authentication message; when PC customer end makes calls, it will send ID number and field of reauthentication during registration to media gate controller which transfer the ID number field of reauthentication to be server for second time authentication and refuse the calling if it's not passed, or receive the calling and feeding back the called information. |