Anonymous signature device, the signature verification device, anonymous signature method, anonymous signature program and signature verification program

摘要

PROBLEM TO BE SOLVED: To secure a degree of freedom of the number of collaborators for signature as enhancing diversity of a signature system which can be used for anonymity signature.;SOLUTION: In configurations of k-out-of-n anonymity signature, a function to become A_i(sk, r)=A_i(pk, r) is used as a commitment creation function A_i(sk, r) corresponding to at least a part of signature authority persons, a function A_i(pk, F_i(pk, s)(-)_ic) when a two-term operations a(+)_ib and a(-)_ib are defined as an operation which satisfies (a(+)_ib)(-)_ib=a is used as a commitment restoration function V_i(pk, s, c) and a function I_i(sk, c(+)_ir) when an inverse permutation function of F is defined as I_i is used as a response creation function Z_i(sk, r, c). Then, the anonymity signature is created and verified by switching the commitment creation function A_i(sk, r), the commitment restoration function V_i(pk, s, c) and the response creation function Z_i (sk, r, c) according to a signature system used by the signature authority persons.;COPYRIGHT: (C)2005,JPO&NCIPI