Patents by Inventor Katsuko Nishioka

Katsuko Nishioka has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).

  • Method of managing digital signature, apparatus for processing digital signature, and a computer readable medium for recording program of managing digital signature
    Patent number: 7574605
    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.
    Type: Grant
    Filed: May 17, 2002
    Date of Patent: August 11, 2009
    Assignee: Hitachi, Ltd.
    Inventors: Kouichi Tanimoto, Shinji Itoh, Kunihiko Miyazaki, Narihiro Omoto, Katsuko Nishioka
  • Method of managing digital signature, apparatus for processing digital signature, and a computer readable medium for recording program of managing digital signature
    Publication number: 20030182552
    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.
    Type: Application
    Filed: May 17, 2002
    Publication date: September 25, 2003
    Inventors: Kouichi Tanimoto, Shinji Itoh, Kunihiko Miyazaki, Narihiro Omoto, Katsuko Nishioka