SECURE PARAMETER GENERATING DEVICE AND PARAMETER GENERATING METHOD IN ALGEBRAIC CURVE CRYPTOGRAPHY

摘要

The Stickelberger element computing devicecomputes a Stickelberger element .omega. in an ab cyclotomic;the Jacobian addition candidate value computing devicecomputes the Jacobian addition candidate value j and aprime number p corresponding to the Jacobian additioncandidate value j, based on the prime number a, theprime number b, the size n of an encryption key, and theStickelberger element.omega.; the order candidate valuecomputing device computes a class H consisting of aplurality of candidate values for the order of theJacobian group of an algebraic curve, based on the primenumber a, the prime number b, and the Jacobian additioncandidate value j; the security judging device searchesfor a candidate value h meeting a security conditionsuch as almost prime number characteristic from theclass H; and the parameter deciding device computes aparameter of an algebraic curve whose order of theJacobian group is in accord with the candidate value h,of the algebraic curves specified by the prime number a,the prime number b, and the prime number p.