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:
Nov. 18, 2014
Filed:
Sep. 28, 2012
Fujitsu Limited, Kawasaki, JP;
Fujitsu Limited, Kawasaki, JP;
Abstract
A cryptographic processing device includes a private key storage unit which stores a private key d for elliptic curve cryptography, a random number generation unit which generates a b-bit random value s, and a processing unit. A bit string D is the private key d or a bit string obtained by modifying the private key d in such a way that a value of a most significant bit is 0, and a relation u=mk+b holds true for a length u of the bit string D, a window size k, and a positive integer m. The processing unit determines a signed k-bit window value w[i] corresponding to each i where 0≦i≦(m−1), a signed b-bit random value s[i] corresponding to each i, and a correction value g. The processing unit determines the above values under a certain constraint condition, while determining each random value s[i] to be +s or −s.