Method for certifying electrical document using digital signature and time stamp

PURPOSE: A method for notarizing an electronic document using an electronic signature and a time stamp is provided to confirm an owner and a notarizing time with respect to an electric document of a user by a notarizing institution. CONSTITUTION: After a notarizing institution system is initialized, a notarizing institution system manager drives a notarizing institution initialization module. A notarizing institution program creates a pair of keys for a cryptogram and a signature to be used in the notarizing institution(S201). Two published notarizing keys out of the created two kinds of key pair are registrated in the notarizing institution system in an off-line method(S202). The notarizing institution system manager confirms a user notarizing request receipt, a requesting waiting management, a notarizing requesting process, a notarizing proof process, and a normally install or not of a sub program providing visual information(S203). For a synchronization of the notarizing institution, visual information of the notarizing institution is adjusted based on visual information of the notarizing institution by making a public institution visual information providing module refer to a visual information providing module of the notarizing institution system once after initially driving a visual information providing module so that the visual information providing module is synchronized the public institution visual information providing module and may maintain an identifying visual information(S204).