Title: Prime calculation device, method, and key issuing system
Application Number: 200480038935 Application Date: 2004.12.21
Publication Number: 1898898 Publication Date: 2007.01.17
Approval Pub. Date: Granted Pub. Date:
International Classifi-cation: H04L9/08;G09C1/00
Applicant(s) Name: Matsushita Electric Ind Co., Ltd. Address:
Inventor(s) Name: Futa Yuichi;Ohmori Motoji
Attorney & Agent: hu jianxin
Abstract:
    There is provided a prime calculation device for calculating a prime without duplication by a simple management of the calculation of the prime. The prime calculation device contains a known prime q and unique management information in the range where the prime is used. The prime calculation device reads out the management information, generates disturbing information R depending on the management information which has been read out, and reads out the prime q. By using the prime q read out and the disturbing information R generated, the prime calculation device calculates a prime candidate N using an equation N = 2 * disturbing information R * prime q 1. The prime candidate N calculated is judged to be a prime or not. If it is judged to be a prime, the calculated prime candidate N is outputted as a prime. Thus, the prime calculation device can calculate a prime candidate from the unique management information without duplication.
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