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:
Sep. 03, 2013
Filed:
Apr. 14, 2011
Hiroshi Maruyama, Tokyo, JP;
Seiji Munetoh, Kanagawa-Ken, JP;
Sachiko Yoshihama, Kanagawa-Ken, JP;
International Business Machines Corporation, Armonk, NY (US);
Abstract
A security device of this invention includes a nonvolatile storage unitfor storing a validity check unit including a counter updated every time signature function meansis called up, a volatile storage unitfor reading and storing a counter array out of an external nonvolatile storage unit storing the counter array, in which the counter array is obtained by coupling a hash value generated for each signature key with a signature number counter for counting the number of signatures performed by use of the signature key, and a hash function unitfor reading the counter array out of the volatile storage unit, generating the hash value, and transferring the hash value to the validity check unit for a validity check.