Abstract: A publication system effective and secure to the publication agency and the user is provided for the publication agency, and a signature verifying function using the disclosed signature log entries is provided for the user. The publication agency discloses the signature log entries received from the users on Web, and acquires time-stamp at the time of the publication, and transmits them together with the publication notice back to the users. The publication agency also has the signature log, and either discloses part of the log at regular intervals in the newspaper or the like, or produces publication-purpose data on the basis of the signature log entries received from each user and discloses in the newspaper. The publication agency, after the newspaper publication, transmits the signature log of the publication agency to the users.

Abstract: A method for signature verification having a structure that reflects reliability of a signature history properly for a hysteresis signature used for verification based on the signature history. A method for arbitration and an arbitrator apparatus solve a dispute on correctness of a signature based on the method for verification. Furthermore, a method for managing history to migrate the management burden on a signer. Reliability is set on a signature issuing record that is a component of a signature history, reliability of the signature history is calculated based on the set reliability, and the calculated reliability is output as reliability of a verification result. The disclosure also provides a method for verification that reflects the reliability of a signature history properly and a method for arbitration and an arbitrator apparatus that solve a dispute on correctness of a signature. Furthermore, a signature history storage service apparatus mitigates the signature history storage burden on a signer.

Abstract: A method of managing digital signature includes the steps of preparing a signature log file storing signature log entry information, generating a new digital signature for a transmission message by reflecting, in the new digital signature, signature log entry information registered to the signature log file in the past; generating signature log entry information associated with the new digital signature and registering the signature log entry information to the signature log file; and preparing a user search file in addition to the signature log file; registering, to the user search file, user identifier information indicating a transmission destination of the transmitted digital signature and a transmission source of the received digital signature, with a correspondence established between the information, the user identifier information, and each signature log entry information in the signature log file.