Patent Document ID: 20080152130
Application ID: 11795267
Patent Status: 0

Claim One:
1. A group signature scheme of a proving apparatus having an input means, a calculating means, and an output means, comprising: a step where the input means reads a data required for calculation; a step where, when N is set to one of security parameters and a knowledge of a discrete logarithm of (a, C) is proven, the calculating means selects at random N integers X — {1j} and calculates X — {1j} for each j by using secret information x′ and the X — {0j}; a step where the calculating means selects r_{ij} for each j and calculating a hash value C_{ij} of a data including the X_{ij} and the r_{ij}; a step where the calculating means calculates L_{j} for each j by raising the a to the power X — {0j}; a step where the calculating means selects a challenge c_j for each j and setting ξ_{j} for each j to the X_{c_jj}; and a step where the output means outputs a data including the {C_{ij}} and the {ξ_{j}}.