Patent ID: 8401179

Claim:
An encryption parameter setting apparatus comprising: a processing device for processing data; a random divisor selection unit; a base divisor generation unit; a pairing log calculation unit; and a parameter setting unit, wherein the random divisor selection unit selects an element from a plurality of elements of a cyclic group G′, as a random divisor D*, by using the processing device; the base divisor generation unit calculates a plurality of base divisors D ˜ j by mapping the random divisor D* by using a plurality of maps G j , where the plurality of maps G j are homomorphism from the cyclic group G′ to each of a plurality of cyclic groups G′ j , based on the random divisor D* selected by the random divisor selection unit, by using the processing device; the pairing log calculation unit calculates logarithms of pairing values of the plurality of base divisors D ˜ j in a group G, where the group G is a direct product of the plurality of cyclic groups G′ j , and a pairing value by a bilinear pairing operation of two elements included in the group G is computable, and treats the logarithms as a plurality of pairing log coefficients η i , by using the processing device; and the parameter setting unit treats the plurality of base divisors D ˜ j calculated by the base divisor generation unit and the plurality of pairing log coefficients η i calculated by the pairing log calculation unit, as encryption parameters used in a cryptographic operation, by using the processing device.