Patents by Inventor Toshiomi Kodama

Toshiomi Kodama 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).

  • Patent number: 7386722
    Abstract: A certificate management method is provided whereby a plurality of service providers have different reliable certificate authorities and, when certificates issued from the certificate authorities are implemented into a smart card, merely by revoking the certificate issued from the certificate authority on which the first service provider relies, all other implemented certificates can be revoked, and the certificates can be individually revoked. A system for implementing the method is provided. The certificate authorities n (n?2) issue a certificate n by using a private key n? corresponding to certificate n? generated by using a certificate 1 issued from a certificate authority 1 which has previously been installed in the smart card and a corresponding private key 1. Thus, the issued certificates have a hierarchical chain relation. When the user wants to revoke all certificates, the certificate 1 issued from the certificate authority 1 is revoked.
    Type: Grant
    Filed: January 30, 2004
    Date of Patent: June 10, 2008
    Assignee: Hitachi, Ltd.
    Inventors: Katsuyuki Umezawa, Hiroki Uchiyama, Seiichi Susaki, Toshiomi Kodama
  • Publication number: 20050120205
    Abstract: A certificate management method is provided whereby a plurality of service providers have different reliable certificate authorities and, when certificates issued from the certificate authorities are implemented into a smart card, merely by revoking the certificate issued from the certificate authority on which the first service provider relies, all other implemented certificates can be revoked, and the certificates can be individually revoked. A system for implementing the method is provided. The certificate authorities n (n?2) issue a certificate n by using a private key n? corresponding to certificate n? generated by using a certificate 1 issued from a certificate authority 1 which has previously been installed in the smart card and a corresponding private key 1. Thus, the issued certificates have a hierarchical chain relation. When the user wants to revoke all certificates, the certificate 1 issued from the certificate authority 1 is revoked.
    Type: Application
    Filed: January 30, 2004
    Publication date: June 2, 2005
    Inventors: Katsuyuki Umezawa, Hiroki Uchiyama, Seiichi Susaki, Toshiomi Kodama