PRIME CALCULATION DEVICE, METHOD, AND KEY ISSUING SYSTEM

摘要

The present invention offers a prime calculating apparatus for calculating a prime which can be determined whether it has been duly generated. The prime calculating apparatus (i) generates a random number, (ii) calculates a multiplication value R by multiplying a management identifier by the random number, and (iii) calculate a prime candidate N, according to N = 2 × (multiplication value R + w) × prime q + 1, with respect to w satisfying an equation of 2 × w × prime q + 1 = verification value (mod management information). Then, the prime calculating apparatus judges whether the calculated prime candidate N is a prime, and outputs the calculated prime candidate N as a prime when determining that it is a prime.