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:
Feb. 24, 2009
Filed:
Jan. 19, 2005
Yuichi Komano, Kawasaki, JP;
Kazuo Ohta, Chofu, JP;
Shinichi Kawamura, Kodaira, JP;
Atsushi Shimbo, Tokyo, JP;
Yuichi Komano, Kawasaki, JP;
Kazuo Ohta, Chofu, JP;
Shinichi Kawamura, Kodaira, JP;
Atsushi Shimbo, Tokyo, JP;
Kabushiki Kaisha Toshiba, Tokyo, JP;
Abstract
According to embodiments of the present invention, in a case where a ground for security is laid in difficulty in executing an inverse function operation of a trapdoor one-way function, represented by an RSA problem, even when a signature order advances, an increase of a size of a key can be inhibited. For example, when the first partial data σexceeding (k+k) bits when concatenating a random number rof kbits is excluded from an input of binary operation on an input side of a signature generation function. Accordingly, a size of an operation result sof the binary operation is set to be constant at (k+k) bits, and, as a result, an input size (key length k bits) of an RSA signature generation function is set to be constant.