Patent ID: 6611597
Filing Date: 2003-08-26
Classification: G06F

Abstract:
An elliptic curve construction device for determining parameters of an elliptic curve E which is defined over a finite field GF(p) and offers a high level of security, p being a prime, the elliptic curve construction device comprising:random number generating means for generating a random number; parameter generating means for selecting the parameters of the elliptic curve E using the generated random number, in such a manner that a probability of a discriminant of the elliptic curve E having any square factor is lower than a predetermined threshold value; finitude judging means for judging whether the elliptic curve E defined by the selected parameters has any point whose order is finite on a rational number field; order computer means for computing an order m of the elliptic curve E when the finitude judging means judges that the elliptic curve E does not have any point whose order is finite on the rational number field; security judging means for judging whether a condition that the computed order m is a prime not equal to the prime p is satisfied; repeat controlling means for controlling the random number generating means, the parameter generating means, the finitude judging means, the order computing means, and the security judging means respectively to repeat random number generation, parameter selection, finitude judgement, order computation, and security judgement until the condition is satisfied, and parameter outputting means for outputting the selected parameters when the condition is satisfied.