PRIME FACTORIZATION APPARATUS, PRIME FACTORIZATION PROGRAM, SAFETY EVALUATION APPARATUS, SAFETY EVALUATION PROGRAM, AND PRIME FACTORIZATION METHOD

摘要

PROBLEM TO BE SOLVED: To provide an individual secret data writing system and an individual secret data writing method for improving convenience of a user.;SOLUTION: A safety evaluation apparatus is provided with a prime factorization section and a safety decision section. In the prime factorization section, prime factorization of N is performed assuming that: N=p*q=(s+a)(s-b); s is an integer close to the square root of N; Nmods=(-a*b)mods; ab=ks-(Nmods); 0abs; and k=1; and whether or not the result of calculation is appropriate is decided. When it is decided as inappropriate, prime factorization is repeated, while increasing k, until it is decided as appropriate. The safety decision section decides, in the case that the appropriate calculation result is not obtained by the prime factorization section even when k exceeds the upper limit (Limit), that a public key encryption using N is safe.;COPYRIGHT: (C)2006,JPO&NCIPI