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:
Aug. 07, 2007
Filed:
Aug. 29, 2001
Masahiro Kaminaga, Sakado, JP;
Takashi Endo, Musashimurayama, JP;
Takashi Watanabe, Kokubunji, JP;
Masaru Ohki, Tokorozawa, JP;
Masahiro Kaminaga, Sakado, JP;
Takashi Endo, Musashimurayama, JP;
Takashi Watanabe, Kokubunji, JP;
Masaru Ohki, Tokorozawa, JP;
Hitachi, Ltd., Tokyo, JP;
Abstract
The subject of the disclosed technology is, when a crypto-processing is performed utilizing an information processing device buried in an IC card, etc., to decrease the relationship between the waveform of the consumption current and the contents of the crypto-processing as a countermeasure against a tamper which observes the waveform of a consumption current. A solution means is shown in the following. When a decryption processing of an RSA cryptogram is performed according to CRT, in stepfor every unit bit block of XP a modular exponentiation calculation is performed, and the partial result of CP up to the calculated bit block is stored in a memory. In stepfor every unit bit block of XQ a modular exponentiation calculation is performed and the partial result of CQ up to the calculated bit block is stored in a memory. In stepa random number is generated, and in stepit is decided that stepis to be executed or stepis to be executed corresponding to the value of the random number.