The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Jun. 10, 2008
Filed:
Jan. 30, 2004
Katsuyuki Umezawa, Machida, JP;
Hiroki Uchiyama, Yokohama, JP;
Seiichi Susaki, Yokohama, JP;
Toshiomi Kodama, Kawasaki, JP;
Katsuyuki Umezawa, Machida, JP;
Hiroki Uchiyama, Yokohama, JP;
Seiichi Susaki, Yokohama, JP;
Toshiomi Kodama, Kawasaki, JP;
Hitachi, Ltd., Tokyo, JP;
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 certificateissued from a certificate authoritywhich has previously been installed in the smart card and a corresponding private key. Thus, the issued certificates have a hierarchical chain relation. When the user wants to revoke all certificates, the certificateissued from the certificate authorityis revoked.