ELLIPTIC CIPHER SAFETY STRENGTH EVALUATION METHOD, ELLIPTIC CIPHER SAFETY STRENGTH EVALUATION DEVICE AND PROGRAM, AND COMPUTER READABLE RECORDING MEDIUM WITH THE PROGRAM RECORDED THEREON

摘要

PROBLEM TO BE SOLVED: To make a method called Weil descent algorithm applicable to an elliptic curve (elliptic cipher) to which an elliptic cipher deciphering method using the Weil descent algorithm can not be applied in a conventional manner.;SOLUTION: An elliptic cipher safety strength evaluation device for evaluating the cipher safety strength of elliptic cipher parameters and their public keys is provided with an input means 401 for inputting prescribed elliptic cipher parameters and their public keys, a computing means 404 for converting the elliptic cipher parameters and their public keys into a hyperelliptic cipher parameters and their public keys, a computing means 405 for converting the hyperelliptic cipher parameters and their public keys into higher order algebraic curve cipher parameters and their public keys, a computing means for computing secret keys based on the higher order algebraic curve cipher parameters and their public keys, and an output means 407 for outputting the result of the computation.;COPYRIGHT: (C)2004,JPO&NCIPI