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:
Oct. 18, 2005
Filed:
Mar. 20, 2001
Takeshi Shimoyama, Kawasaki, JP;
Koichi Ito, Kawasaki, JP;
Masahiko Takenaka, Kawasaki, JP;
Naoya Torii, Kawasaki, JP;
Jun Yajima, Kawasaki, JP;
Hitoshi Yanami, Kawasaki, JP;
Kazuhiro Yokoyama, Kawasaki, JP;
Takeshi Shimoyama, Kawasaki, JP;
Koichi Ito, Kawasaki, JP;
Masahiko Takenaka, Kawasaki, JP;
Naoya Torii, Kawasaki, JP;
Jun Yajima, Kawasaki, JP;
Hitoshi Yanami, Kawasaki, JP;
Kazuhiro Yokoyama, Kawasaki, JP;
Fujitsu Limited, Kawasaki, JP;
Abstract
Intermediate data a, b, c, and dare prepared by an intermediate data preparing equipmentfrom a cryptographic key through a nonlinear type function operation and the like, an extended key preparing equipmentselects a [X], b [Y], c [Z], and d [W] corresponding to the number of stages r from the intermediate data, and rearranges the data as well as conducts that of bit operation to prepare extended keys, whereby an extended key preparing apparatus by which an extended key required in the case where common key cryptosystem is applied can be safely prepared at a high speed, a process for preparing such an extended key, and a recording medium used therefor are provided.