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:
Mar. 20, 2007
Filed:
Jul. 12, 2001
Hirofumi Muratani, Kawasaki, JP;
Masahiko Motoyama, Yokohama, JP;
Kenji Ohkuma, Yokohama, JP;
Fumihiko Sano, Fuchu, JP;
Shinichi Kawamura, Kodaira, JP;
Hirofumi Muratani, Kawasaki, JP;
Masahiko Motoyama, Yokohama, JP;
Kenji Ohkuma, Yokohama, JP;
Fumihiko Sano, Fuchu, JP;
Shinichi Kawamura, Kodaira, JP;
Kabushiki Kaisha Toshiba, Kawasaki, JP;
Abstract
Expanded key schedule circuit for common key encryption system in which expanded keys are used in a predetermined order in data randomizing process for encryption and in a reversed order in data randomizing process for decryption, comprises round processing circuits connected in series. The round processing circuits subject the common key or sub key of a previous stage to a round function to output a sub key. The sub key of the last stage is equal to the common key. The expanded keys are generated from the sub keys.